Biomedical subjects

E D Heller

Publications and source records attributed to E D Heller.

At least 19 recordsLinked to original sources

PubMed2004

The effect of growth medium salinity of Photobacterium damselae subsp. piscicida on the immune response of hybrid bass (Morone saxatilis x M. chrysops).

Photobacterium damselae subsp. piscicida (P. damselae) was grown on various media and the effect of media salinity on certain immune responses of hybrid bass was studied. In Israel, pasteurellosis outbreaks have not been reported at water salinities below 1.38 per thousand. During vaccination experiments the salinity of the medium on which P. damselae is grown, was shown to affect stimulation of the immune system. No correlation was found between antibody response and protection. Bacterial envelopes separated by electrophoresis and subjected to western blot analysis revealed an antibody response against some protein bands. Band sequencing was performed to identify the protein stimulating the immune response. Sequence identity of 80% was seen in 10-amino-acid overlap of the 36-kDa band with a specific gene of alkalophilic Bacillus firmus. A preparation of P. damselae grown in a 2.5% NaCl medium at 25 degrees C is the most effective vaccine against pasteurellosis, providing hybrid bass with quite good protection.

Amino Acid Sequence↗

PubMed2003

The effect of storing hybrid bass (Morone saxatilis x M. chrysops) sera at freezing temperatures on antibody titers.

The effect of storing hybrid bass sera at freezing temperatures on their enzyme-linked immunosorbent assay (ELISA) titers was determined, and the precipitate formed during storage was characterized. Frozen bass sera from fish vaccinated with bacterial sonicate showed no titer in either of two groups-one immunized with bacterial sonicate and the other with sonicate emulsified in adjuvant. Fresh sera exhibited average titers of 1:32 in both groups and 1:20 in convalescent serum. Hybrid bass antisera to bovine serum albumin showed maximum ELISA OD when sera were used after a short storage at 4 degrees C. Storage at freezing temperatures (-20 and -73 degrees C) reduced the OD value substantially. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of the cryoprecipitate formed after freezing hybrid bass sera showed protein bands at 85 and 38 kDa, most probably the heavy and light chains, respectively, of bass IgM. Bands at 55, 52, 28, and 26 kDa may represent fibrinogen subunits. It is possible that the cryoprecipitate is composed of a fibrinogen net, which traps the tetrameric IgM molecules and precipitates them during frozen storage.

Animals↗

PubMed2003

Staphylococcus aureus exosecretions and bovine mastitis.

The role of Staphylococcus aureus and coagulase-negative staphylococcal exosecretions in bovine udder infection was tested by monitoring the cows' response to in vivo inoculation of bacterial exosecretions into udder quarters. Twenty Israeli-Holstein dairy cows were included in the study; two or three of the udder quarters of each cow were intracisternally inoculated with 0.04-0.05 mg/quarter (total proteins) of the various sterile bacterial exosecretions in a sterile pyrogen-free saline. Each udder was inoculated with two or three different bacterial exosecretions or placebo (Columbia Broth). Cows were monitored for 96 h post-inoculation for rectal temperature, heart and respiratory rates, alimentary tract activity (rumen contraction), udder temperature, pain, oedema and udder size. Milk samples were examined bacteriologically and for somatic cell count, N-acetyl-D-glucosaminidase (NAGase) activity and somatic cell differentiation. No enterotoxins (beta-G) or toxic shock syndrome toxin-1 were detected in response to any of the bacteria tested. Control quarters or those inoculated with Columbia Broth, showed similar NAGase and somatic cell count values throughout the experiment. Twelve of the 18 strains tested, induced inflammation in the inoculated quarters while six did not. Of the 12 strains causing local inflammation, only six were found significantly different from the control and were considered as high response (group 1). The other six that caused a local inflammation did not differ significantly from the control, and were considered to be moderate response (group 2). The six S. aureus isolates that did not cause an inflammatory response were considered to have low response (group 3). In all quarters inoculated with S. aureus bacterial exosecretions belonging to groups 1 and 2, the polymorphonuclear cells and macrophages were proportionally increased while CD4+ and CD8+ T-lymphocyte populations decreased. One-dimensional NuPAGE (7%) Tris-acetate gel electrophoresisof the bacterial exosecretions revealed four different bands appearing between 36 and 31 kDa, marked from top to bottom as A, B, C and D. An association was found between the combinations of expressed bands and the cow responses: the majority of the cases could be linked to the expression of bands B and C.

Acetylglucosaminidase↗

PubMed2002

Microsatellite markers associated with quantitative trait loci controlling antibody response to Escherichia coli and Salmonella enteritidis in young broilers.

A unique resource population was produced to facilitate detection of microsatellite markers associated with quantitative trait loci controlling antibody (Ab) response in broiler chickens. Three F1 males were produced by mating two lines divergently selected on Ab response to Escherichia coli vaccination. Each F1 male was mated with females from four genetic backgrounds: F1, high-Ab line (HH), low-Ab line and commercial line, producing three resource families, each with four progeny types. About 1700 chicks were immunized with E. coli and Salmonella enteritidis vaccines. Selective genotyping was conducted on the individuals with highest or lowest average Ab to E. coli and S. enteritidis within each progeny type in each sire family. Twelve markers were significantly associated with Ab to E. coli and six of them were also associated with Ab to S. enteritidis, mostly exhibiting a similar low effect (approximately 0.35 phenotypic SD) in all progeny types. Four markers exhibited a highly significant and much larger effect (approximately 1.7 SD), but only in progeny of females from the HH, suggesting that a backcross to the high parental line should be preferred over the commonly used F2 population. Results from two markers suggested a quantitative trait locus on chromosome 2 around 400 cM. The marker MCW0083, significant in two sire families, is closely linked to the bone morphogenetic protein 2 (BMP2) gene, known to be associated with the control of T-cell transformation in humans.

Animals↗

PubMed2002

Influence of Staphylococcus aureus exosecretions isolated from bovine mastitis on leukocyte activity in vitro.

The role of Staphylococcus aureus and coagulase-negative staphylococcal exosecretions was tested for its ability to elicit in vitro proliferation of bovine blood lymphocytes, which we determined by means of the 3H-thymidine proliferation assay and by flow cytometry. Exosecretions of 32 field strains of S. aureus isolated from bovine udder infection and one of each of S. intermedius (M2), S. hyicus (M5), S. xylosus (M6) and S. chromogenes (M10) were used. Of the 32 S. aureus bacterial exosecretions, only 14 stimulated bovine mononuclear cells to proliferate. A high degree of association was found when the proliferation indexes were compared with the virulence as determined by intracisternal inoculation. All the six S. aureus strains that were categorized as highly virulent and that were tested in the proliferation assay exhibited a proliferation index > 20, whereas the five S. aureus strains that were categorized as low did not stimulate at all. Cells treated with media or Columbia broth supplemented with 0.1% D-glucose, yeast extract, and 0.5% NaCl (CBs) did not exceed 15% of the T-cells double positive with CD25+, whereas incubation with Con A activated the T-cells to display CD25+ up to 90%. Cells treated with one of the exosecretions that stimulated bovine mononuclear cells to proliferate, stimulated CD3+ and CD4+ T-cells to exhibit CD25+ receptor significantly higher (P < 0.05) than that found in media and CBs treatments, but lower than those found in Con A treatments. The exosecretions that did not stimulate mononuclear cells to proliferate also did not activate T-cells to exhibit CD25+ receptor. Con A activated 74% out of the total CD8+ to exhibit ACT2 receptor and 50% out of the total CD4+ to exhibit ACT3 receptor. A few but not all of the exosecretions that activated the CD25 receptor on T-cells also activated the ACT3 receptor on CD4+ cells.

Animals↗

PubMed2002

Antibody responses and morbidity following infection with infectious bronchitis virus and challenge with Escherichia coli, in lines divergently selected on antibody response.

We evaluated the association between antibody (Ab) production and disease resistance. A controlled-challenge protocol was developed to mimic natural infection and to yield a higher rate of mortality following Escherichia coli (EC) challenge. Chicks were first infected with infectious bronchitis virus (IBV) by injecting a high dose of vaccine (attenuated virus) into their air sacs and then were infected with pathogenic EC introduced intratracheally. The experimental population consisted of lines divergently selected for high (HH) or low (LL) Ab response to EC vaccination, an HH x LL cross (HL), and commercial broilers (CC). When chicks were vaccinated with EC vaccine, mean Ab titer 15 d post-EC challenge was threefold higher in HH than LL lines, but both lines exhibited very low mortality (approximately 2%). When chicks were not vaccinated prior to EC challenge, high mortality (8 to 20%) occurred in the slow-growing HH, LL, and HL lines, and much higher mortality (approximately 40%) occurred among the CC broilers that were 38% heavier than the HH, LL, and HL lines. Mean level of Ab to EC, 7 d after EC challenge, was about twofold higher in HH vs. LL chicks and intermediate in HL and CC chicks. Within each line, Ab levels were higher in chicks exhibiting colibacillosis than in healthy ones, suggesting that these Ab were produced as a result of ongoing infection but were too late to fully prevent morbidity and mortality. These results indicate that rapid growth rate substantially reduces broiler viability, whereas Ab levels produced in response to acute pathogenic challenge without prior vaccination do not contribute to disease resistance. Among the relatively slow-growing lines, mortality was about twofold higher in HH than in LL lines. This finding may confirm previous reports that without prior vaccination, high Ab response to acute challenge increases consequent mortality; alternatively, the LL line may be superior in nonspecific defense mechanisms.

Animals↗

PubMed2002

Genetic and phenotypic correlations between antibody responses to Escherichia coli, infectious bursa disease virus (IBDV), and Newcastle disease virus (NDV), in broiler lines selected on antibody response to Escherichia coli.

The genetic control of antibody (Ab) response to Escherichia coli (EC), infectious bursa disease virus, and Newcastle disease virus and the genetic and phenotypic correlation between these Ab responses, were evaluated under farm conditions in which chicks were simultaneously exposed to these antigens. The experimental population comprised five groups: two lines divergently selected for high (HH) or low (LL) Ab response to EC vaccination; a commercial broiler dam-line (CC), from which HH and LL had been derived; and the HH x CC and LL x CC hybrid groups (HC and LC, respectively). Lines LL and HH expressed similar symmetric divergence to all three antigens. The ranking of the LL, LC, CC, HC, and HH genetic groups according to their mean Ab responses and their very high linear correlation with the LL vs. HH genomic scale clearly indicate the additive nature of the genetic divergence between these lines. Several estimates of correlation were calculated between Ab responses of each pair of antigens and between BW and Ab to each antigen. The high correlation between group means, the near-zero within-group correlation, and the low phenotypic correlation indicate the strongly positive genetic correlation between Ab responses and no correlation with BW. The results of this study suggest that overall immunocompetence of commercial broilers can be improved by selection for high Ab response of young chicks to controlled immunization with a single antigen, without counteracting further selection for high BW.

Animals↗

PubMed2001

The effect of apramycin on colonization of pathogenic Escherichia coli in the intestinal tract of chicks.

The purpose of the present study was to examine the effect of apramycin sulphate on the colonization of pathogenic E. coli in the intestines of chicks. Apramycin treatment (0.5g/l in the drinking water) of 3-to 5-week-old Leghorn chicks for 24 or 48 hours resulted in a reduction, to an undetectable level, in the number of coliforms in the digestive tract for at least the first 24 h. Per os inoculation of E. coli (O2:K1) after 24 to 48 h of treatment resulted in a significant decrease in colony forming units (cfu) in the digestive tract of the treated chicks. Food deprivation from the time of inoculation did not significantly change the results. However, food and water deprivation caused bacteraemia in a number of the control chicks but not in the treated chicks. Comparison of the level of protection between Leghorn and broiler (Anak strain) chicks revealed that there was a significantly higher (P<0.05) level of bacteraemia in the broiler than in the Leghorn chicks. Chicks treated with 0.25 g/l or 0.125 g/l apramycin for 24 or 48 h before E. coli inoculation showed significantly lower cfu in the colon and caecum than untreated control chicks, but significantly higher cfu were found in the colon than in chicks treated with 0.5 g/l apramycin. Although in vitro preincubation of apramycin with ileum cells did not decrease the percentage of cells to which the bacteria adhered, the number of bacteria adhered per cell decreased significantly. Taken together, our in vitro and in vivo results show that apramycin is effective against E. coli by preventing colonization of the gut by the bacteria, which could lead to a reduction of colibacillosis in poultry.

Animals↗

PubMed2001

Immune response and resistance to infectious bursal disease virus of chicken lines selected for high or low antibody response to Escherichia coli.

Two experimental broiler lines were developed by divergent selection for high (HH) and low (LL) antibody response to Escherichia coli. Antibody response of these lines to immunization with a commercial vaccine (whole inactivated virus, WIV) against infectious bursal disease virus (IBDV) or with proteins VP2 and VP3 of that virus, and their resistance to challenge with a virulent IBDV, were tested. The study was performed with 213 male and female chicks from the tenth generation of the HH and LL lines. At 15 d of age, after disappearance of maternal antibodies, chicks from each line were randomly divided into four groups and injected with WIV, VP2, VP3, or adjuvant alone as a negative control. Chicks were bled 18 d postinjection, and antibody titers were determined by ELISA. Ten days later, the chicks were challenged with a virulent strain of the virus and killed after 10 d; the ratio of bursa of Fabricius to 100 g BW was determined for each bird. Significant differences in antibody titers were found among immunized and control chicks. Chicks from the HH line exhibited significantly higher antibody titers than LL chicks in response to WIV and VP2 vaccines but not to VP3 vaccine. Following challenge, bursa weight (relative to BW) of HH and LL chicks vaccinated with WIV and VP2 was significantly higher (P < 0.01) than that of chicks vaccinated with VP3 or the challenged unvaccinated control. No difference was found in this parameter between the latter two groups. Possible explanations for the differences in the line response to VP2 and VP3 are discussed.

Animals↗

PubMed2000

Immunocompetence and viability under commercial conditions of broiler groups differing in growth rate and in antibody response to Escherichia coil vaccine.

Mortality and morbidity due to infectious diseases are an increasing source of losses to the broiler industry. Breeding chickens for improved disease resistance may reduce these losses. A study was designed to evaluate the contribution of selection for immune response to viability of broilers under farm conditions. The experimental populations consisted of six groups: two lines divergently selected for high (HH) or low (LL) antibody (Ab) response to Escherichia coli vaccination; commercial broilers (CC); and the HH x CC, LL x CC, and HH x LL crosses. Chicks were tested under standard vaccination program and management on commercial farms in two years (1997 and 1998). Mortality was recorded in the whole groups, each consisting of several hundred or thousand of chicks, whereas BW and Ab to natural exposure to E. coli and to vaccination with Newcastle disease virus (NDV) were determined in samples of 50 to 120 chicks/group per yr. Groups were clustered into three levels of BW: CC representing contemporary fast-growing broilers; HH, LL, and HL representing broilers 10 yr earlier; and HC and LC with intermediate BW. The HH and LL groups exhibited the highest and lowest E. coli Ab titers, respectively. Mean Ab of the CC group equaled the average of the selected lines, and all crosses exhibited mid-parent Ab titers, indicating additive genetic control. Group means for Ab to NDV were highly correlated with those of E. coli, suggesting a common genetic control for the immune response to these two antigens. In both years, the highest mortality was found in the fast-growing group (CC), and the lowest mortality was in the slow-growing HH, LL, and HL groups. In the crosses, despite their similar mean BW, mortality was one-third higher among LC vs. HC birds. These results suggest that Ab response and potential growth rate interact in their effect on mortality due to infectious diseases.

Animals↗

PubMed1999

Relationship between resistance to complement, virulence and outer membrane protein patterns in pathogenic Escherichia coli O2 isolates.

To establish a possible relationship between resistance to complement, virulence and outer membrane protein banding patterns, ten E. coli O2 strains isolated from chickens with colibacillosis were studied for: (1) resistance to the bactericidal effect of complement by a quantitative microtiter method, (2) virulence, as determined by chicken lethality test, and (3) outer membrane protein banding patterns yielded by SDS-polyacrylamide gel electrophoresis. The ten isolates were classified into three groups: (1) Group 1, consisting of four isolates showed: (a) high resistance to complement, (b) high virulence, and (c) different pattern between 35 and 40 kDa with a weak peptide band at 35 kDa. (2) Group 2, consisting of one isolate showed: (a) high resistance to complement, (b) low virulence, and (c) a weak peptide band at 35 kDa. (3) Group 3, consisting of five isolates showed: (a) low resistance to complement, (b) low virulence, and (c) identical OMP pattern between 35 and 40 kDa exhibiting a strong peptide band at 35 kDa. The results suggest that high resistance to complement may be necessary but no sufficient for virulence and that OMP banding patterns may be a marker for virulence.

Animals↗

PubMed1999

Major histocompatibility complex (MHC) related cDNA probes associated with antibody response in meat-type chickens.

The major histocompatibility complex (MHC) region was examined as a set of candidate genes for association between DNA markers and antibody response. Intercross F2 families of chickens were generated from a cross between high (HC) and low (LC) Escherichia coli(i) antibody lines. Restriction fragment length polymorphism (RFLP) analysis was conducted by using three MHC-related cDNA probes: chicken MHC class IV (B-G), chicken MHC class I (B-F), and human MHC-linked Tap2. Association between RFLP bands and three antibody response traits (E. coli, sheep red blood cells and Newcastle disease virus) were determined by two methods: by statistically analyzing each band separately and also by analyzing all bands obtained from the three probes by using multiple regression analysis to account for the multiple comparisons. The MHC class IV probe was the highest in polymorphisms but had the lowest number of bands associated with antibody response. The MHC class I probe yielded 15 polymorphic bands of which four exhibited association with antibody response traits. The Tap2 probe yielded 20 different RFLP bands of which five were associated with antibody production. Some Tap2 bands were associated with multiple antibody response traits. The multiband analysis of the three probes' bands revealed more significant effects than the analysis of each band separately. This study illustrates the efficacy of using multiple MHC region probes as candidate markers for quantitative trait loci (QTLs) controlling antibody response in chickens.

Animals↗

PubMed1997

Chicken-embryo fibroblasts produce two types of interferon upon stimulation with Newcastle disease virus.

Controversy has long surrounded the question of whether chickens, like mammals, can produce two types of interferon (IFN). Recently, type-I and type-II chicken IFNs have been cloned. Our study focuses on the further characterization of native fibroblast and spleen IFNs and shows that chicken embryo fibroblasts (CEFs) produce a mixture of type-I and type-II IFNs. IFN was purified by three different methods, controlled pore-glass chromatography, ion-exchange chromatography and preparative SDS-PAGE. Three protein bands showing IFN-like anti-viral activity, from CEFs which had been virus-stimulated for IFN production, were detected at 25, 27 and 29 kDa. Polyclonal antibodies produced against these bands showed partial cross-reaction with purified media from mitogen-stimulated spleen cells in ELISA, western blot analysis and anti-viral activity neutralization assay. Differences between purified conditioned media from CEF and spleen were found with respect to the stimulation of macrophages for nitric oxide production, pH stability and signal transduction pathways; only CEF IFN activated the IFN-stimulated gene factor-3 complex, whereas both CEF and spleen IFNs activated the IFN regulatory factor-1 gene. These findings concur with the differences that are known to exist between mammalian type-I and type-II IFNs. Attempts at sequencing the 25 and 27 kDa proteins by Edman degradation yielded evidence of N-terminal blockage.

Animals↗

PubMed1996

Genetic differences and heritability of antibody response to Escherichia coli vaccination in young broiler chicks.

Broiler chicken lines, selected divergently for high (HC) or low (LC) antibody titer to Escherichia coli vaccination at an early age, were evaluated for antibody response at the S5 and S9 generations of selection. The full-pedigreed populations consisted of about 300 and 400 chicks per line in S5 and S9, respectively. At S5, all chicks were vaccinated at 10 d of age (VA10) and antibody titer was determined twice for each chick, at 8 and 12 d postvaccination (dPV). At S9, each line was divided into two equal groups; in the HC line, one group was vaccinated at 8 d of age (VA8), and the other at 10 d of age (VA10), whereas in the LC line, one group was VA10 and the other was VA12. Antibody titers were determined twice for each chick, 8 and 10 dPV. The effects of line, age at vaccination (VA), and days for antibody development (dPV) were tested, and the heritability of antibody titer was estimated for each line-VA-dPV set of data. The HC and LC lines differed significantly in the maturation process of their immune systems. The percentage of chicks with detectable antibody at 18 d of age (VA10-8 dPV) among HC chicks was significantly higher than among LC chicks (85 vs 48% in S5 and 96 vs 63% in S9). In S9, 90% of the HC chicks had already responded at 16 d of age and 100% at 18 d of age, whereas among the LC chicks, only 62% were positive at 18 d of age, increasing to no more than 98% at 22 d of age. The results demonstrates that selection of antibody titer to E. coli vaccination at 20 d of age actually affects the earliest age of immune response, as the immune system of the HC chicks matures earlier than that of the LC chicks. The HC S9 chicks at 8 dPV exhibited a fourfold higher antibody titer than their LC 8 counterparts. This difference further increased at 10 dPV, indicating that the lines differed not only in the level of antibody at a specific age, but also in their rate of antibody titer development. The highest estimate of heritability was very similar in both lines (0.44 and 0.42 in HC and LC, respectively). However, in the HC line this heritability was exhibited at 18 d of age, and only at 22 d in the LC line. Thus, both lines have a similar amount of genetic variation for early immune response, but in the HC line this variation is fully expressed 4 d earlier than in the LC line. These results suggest that selection for high or low antibody response in young chicks results in early or late antibody production, respectively. To maximize the efficiency of selection for early immune response, one must determine the best vaccination age and timing of antibody evaluation in any given population, and these values must be revalidated and updated as selection proceeds.

Age Factors↗

PubMed1996

Effects of gonadal steroids and their antagonists on the humoral immune response of immune-selected broiler chicks.

The effects of gonadal hormones, testosterone (Te) and estrogen (E2) as factors in the development of the immune system in two lines, high response (HC) and low response (LC), of broiler chickens divergently selected for early or late immune maturation were studied. For this purpose, plasma Te and E2 levels were tested and correlated with immune response. Also, the effects of exogenous administration of gonadal steroids testosterone propionate (TP), dihydrotestosterone (DHT), and estradiol 3-benzoate (EB), and the nonsteroidal androgen antagonist flutomide (Flu) and anti-estrogen tamoxifen (Tam) on the immune system were studied. Male chicks of the LC line had a higher level of endogenous Te during first 30 d posthatch. The administration of TP or DHT had no noticeable effect on the humoral immune response, whereas DHT suppressed growth of the bursa of Fabricius of both sexes of HC line. No differences in the endogenous E2 level were observed between sexes in either line. Administration of EB inhibited comb and testicle growth and enhanced significantly the humoral immune response to Escherichia coli and sheep erythrocytes (SRBC). The anti-androgen Flu and anti-estrogen Tam strongly inhibited humoral immune response to E. coli and SRBC antigen, whereas no effects on comb and testicle growth were observed. The experimental results suggest that gonadal hormones have similar principal posthatch effects in avian as in mammals; however, the gonadal steroids prehatch effects and the genetic-physiological-environmental effects require further study.

Analysis of Variance↗

PubMed1994

Parental effect on the humoral immune response to Escherichia coli and Newcastle disease virus in young broiler chicks.

Genetic and environmental variables influence animal resistance to disease infection. In addition, maternal effects were also found in studies with egg-type chicken lines. In our laboratory, meat-type chicken lines were divergently selected for either early or late maturation of the immune system, based on family and individual antibody responsiveness at 10 d of age. The high-antibody (HC) and low-antibody (LC) lines differed significantly in the early immune response to Escherichia coli, to Newcastle disease virus (NDV) vaccination, and to several other immune functions. Reciprocal crosses between the HC and LC lines were performed over 2 yr at three different locations. Immune responses to E. coli and NDV vaccination provided separate estimates of maternal and paternal effects. Dam effect on immune response to E. coli vaccine was significantly larger than sire effect; the antibody titer in both reciprocal crosses was intermediate between the parental lines, but the mean titer of the HC x LC cross was significantly lower than that of the LC x HC cross. Similar, but not significant, ranking of crosses was observed for the response to NDV. Evidently, the level of the offspring humoral immune response was more a dam than a sire effect.

Animals↗

PubMed1993

Designation by restriction fragment length polymorphism of major histocompatibility complex class IV haplotypes in meat-type chickens.

Major histocompatibility complex (MHC) class IV haplotypes were identified in a population of meat-type chickens by restriction fragment length polymorphism (RFLP) analysis. Fourteen different haplotypes were designated on the basis of restriction patterns obtained from Southern blots of PvuII- or BglII-digested DNA, hybridized with the MHC class IV cDNA probe bg32.1. Digestion with each restriction enzyme yielded the same level of polymorphism among individuals. For each haplotype, 4-10 restriction fragments ranging from 0.8 to 8 kb were observed. Such a designation of meat-type chicken MHC class IV haplotypes enables a rapid recognition of previously defined haplotypes, is readily adjustable to additional, newly found restriction patterns and could prove useful in practical breeding programmes.

Animals↗

PubMed1992

Immunological parameters in meat-type chicken lines divergently selected by antibody response to Escherichia coli vaccination.

Our group has established two lines of meat-type chickens divergently selected for early (HC line) and late (LC line) antibody responsiveness at 10 days of age to immunization with inactivated pathogenic Escherichia coli bacteria. The question addressed in the study presented here is whether this selection has changed other immunological responses, increasing the overall 'early' immunocompetence. Broilers of the third and fourth generations (S3 and S4) of the selected lines (HC and LC) and a control, unselected line (CT) were vaccinated at 10 days of age with E. coli vaccine, Newcastle virus vaccine (NDV), sheep erythrocytes (SRBC) or bovine serum albumin (BSA). Line-HC chicks exhibited higher antibody titers to E. coli, NDV and SRBC than CT or LC chicks. At 20 days of age HC chicks demonstrated a higher total protein and a higher beta- and gamma-globulin levels in their serum. At 21 days of age, HC chicks cleared carbon particles faster than LC chicks. Peripheral blood lymphocytes (PBL) from HC chicks vaccinated with E. coli vaccine, proliferated in vitro more actively in the presence of the stimulating antigen than the PBL of LC chicks. Peripheral blood lymphocytes (PBL) obtained from HC-line chicks exhibited a higher proliferative response to concanavalin A (Con A)-, phytohemagglutinin (PHA)- or pokeweed mitogen (PWM)-stimulation than LC PBL. These results demonstrate that the selection for high or low antibody response to E. coli at a young age resulted also in a significant change in the response of other parameters of the immune system. The high response to E. coli was found to be associated with a high antibody response to other antigens (NDV and SRBC), increased phagocytic activity and increased proliferative response to antigen or mitogens. The selection most probably affected early immunocompetence.

Aging↗