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Biomedical subjects

C R Stokes

Publications and source records attributed to C R Stokes.

At least 91 records · Page 5Linked to original sources
PubMed1991

Mucosal priming of T-lymphocyte responses to fed protein antigens using cholera toxin as an adjuvant.

Cholera toxin is widely recognized as a potent stimulator of mucosal IgA responses after oral feeding. However, comparatively little is known of its ability to stimulate cellular responses. This is due in part to the direct inhibitory effects of cholera toxin on T lymphocytes, which can confound attempts to study primed T-cell responses in vitro. We have avoided this problem by using cholera toxin as an adjuvant to enhance the response to an unrelated protein fed simultaneously. Thus the simultaneous feeding of 10 micrograms of cholera toxin and 5 mg of keyhole limpet haemocyanin (KLH) results in the priming of T cells in the spleen, mesenteric lymph nodes, Peyer's patch and lamina propria that proliferate when restimulated with KLH in vitro. The feeding of KLH alone does not result in such responses. Both CD4- and CD8-positive antigen-specific T cells were involved in the response and the cells produced both interleukins 2 and 4 on antigen restimulation in vitro.

Adjuvants, Immunologic↗
PubMed1990

Effect of susceptibility to endometritis on specific antibody in the endometria of mares.

Endometrial biopsies were collected on two occasions from mares resistant to (n = 3) and once from mares susceptible to persistent endometritis (n = 6). The endometrial tissue was minced and cultured in vitro for 24 h. No hemolytic complement activity was detected in the endometrial culture supernatant. Endometrial culture supernatant from mares with persistent endometritis contained titers of antibodies to Streptococcus zooepidemicus similar to those from resistant mares. However, the culture supernatant of biopsies from mares with endometritis was less effective (P < 0.05) at opsonizing S. zooepidemicus in vitro.

Journal Article↗
PubMed1990

Fate and uptake of soluble and particulate antigens in the preparturient bovine mammary gland.

Pregnant heifers were infused intramammarily with ovalbumin in one quarter and killed S. uberis in another quarter. The animals were slaughtered at time intervals after infusion, and tissues were collected from different parts of the gland and from the local lymph nodes. Ovalbumin and bacteria reached the lymph nodes as early as 1 and 3 h after infusion respectively. Ovalbumin was also present in blood 5-10 min after infusion and in non-infused quarters. Both ovalbumin and bacteria were phagocytosed by the epithelium of the mammary gland. However, bacteria were seen in the tissues in small numbers at all stages after infusion. Larger numbers were phagocytosed by neutrophils in the lumen of ducts, 18 h after infusion. Phagocytosis of both ovalbumin and bacteria was not present in the connective tissue of the gland. The results indicate increased permeability of the preparturient gland to soluble proteins, but limited uptake of bacteria. Furthermore, a mechanism of transfer of antigens among quarters has been suggested.

Animals↗
PubMed1990

Whole cholera toxin and B subunit act synergistically as an adjuvant for the mucosal immune response of mice to keyhole limpet haemocyanin.

Cholera toxin (CT) is a potent stimulator of IgA responses when administered orally and has been shown to promote IgA responses to a second protein such as keyhole limpet haemocyanin (KLH) if this is fed simultaneously. In this paper we show that whilst feeding 5 mg KLH with either 0.5 micrograms CT or 10 micrograms B subunit fails to stimulate a mucosal IgA response to KLH, feeding 0.5 microgram CT and 10 micrograms B subunit together with 5 mg KLH produces a local IgA anti-KLH response as great as that produced by 10 micrograms of whole CT. In addition to stimulating IgA responses in the lamina propria, preliminary results indicate that cellular responses are also stimulated, as we have demonstrated KLH antigen-driven proliferation of cells isolated from groups of mice fed either 10 micrograms CT + 5 mg KLH or 0.5 micrograms CT + 10 micrograms CTB + 5 mg KLH but not mice fed KLH alone or with either 10 micrograms CTB or 0.5 micrograms CT. These results indicate that the mucosal adjuvant action of CT is due to a synergistic effect involving both the GM1 binding of the B subunit and adenylate cyclase activation by the A subunit.

Adenylyl Cyclases↗
PubMed1990

Expression and distribution of Ia antigen in the murine small intestine. Influence of environment and cholera toxin.

Density and distribution of Ia antigen in the small intestine of C57bl/6 mice showed substantial differences, depending on the environment in which they were reared and maintained. Isolator-reared mice expressed low levels of epithelial Ia antigen in comparison to mice reared in a conventional environment. Oral administration of 10 micrograms of cholera toxin had no effect on the level of epithelial Ia expression. We conclude, therefore, that the mechanism whereby cholera toxin is able to potentiate mucosal responses to fed antigens is not related to changes in the level of epithelial Ia expression.

Animals↗
PubMed1990

Investigation into factors influencing performance of the canine antiglobulin test.

Antiglobulin (Coombs') reagents were assessed for their ability to detect immunoglobulin and complement attached to red cells. Polyspecific and monospecific reagents were prepared using a number of immunisation protocols. Performance of these antisera against control red cells was compared, in a direct Coombs' test, with samples from cases of canine autoimmune haemolytic anaemia (AIHA). A combined reagent containing two monospecific antisera (anti-IgG + anti-C3) gave optimum results. Positive control red cells were required to standardise canine Coombs' reagents for the laboratory diagnosis of AIHA. The optimum incubation temperature for the canine Coombs' test was shown to be 37 degrees C.

Anemia, Hemolytic, Autoimmune↗
PubMed1989

The effect of parenteral immunisation on antibody production in the pig colon.

Local and systemic antibody production was studied in pigs to compare responses to live and killed bacterial antigen and purified protein antigen, with and without prior mucosal stimulation. Recovery from challenge with live bacteria and intramuscular injection with killed bacteria gave rise to similar high levels of serum IgG antibody, but the ratio of specific IgA to IgG in the colon was significantly higher after infection than following vaccination with killed bacteria. Vaccination with a protein antigen gave rise to serum and local antibody production. Prior feeding of the antigen had a tolerising effect on the serum antibody response, but production of IgG and IgA antibody by the colon was not suppressed.

Animals↗
PubMed1989

Clinical and laboratory findings in cats infected with feline immunodeficiency virus.

Thirty-two cats referred to the Feline Studies Centre between June 1987 and October 1988, and 14 in-contact cats, were found to be infected with feline immunodeficiency virus. Most of the 46 cats were non-pedigree and free ranging; 27 were male (19 neutered) and 19 were female (18 neutered). Their ages ranged from one to 17 years and the average age was 5.8 years. The most common clinical signs were lethargy, inappetence, weight loss, pyrexia and lymphadenopathy; most cases had multiple abnormalities. Other common signs were gingivitis, diarrhoea, rhinitis and ocular discharge. Eight cats had neoplasia. The commonest haematological abnormalities were anaemia, neutropenia, lymphopenia and monocytosis. Eight cats had lymphocytosis; seven of these were in a single house-hold. Several cats had high serum globulin levels and half of those tested had high IgG levels. Seven cats had no detectable antibody to feline immunodeficiency virus even though the virus was cultured from the peripheral blood lymphocytes. During follow-up for up to 60 weeks one cat died and 23 were destroyed on humane grounds.

Age Factors↗
PubMed1989

Effect of age on absorption and immune responses to weaning or introduction of novel dietary antigens in pigs.

Pigs weaned at three weeks old absorb food protein antigens from the intestine. The amount of antigen absorbed declines over the next three weeks, and this decline is associated with an increasing level of serum antibody to the fed proteins. There was no difference in the rate of immune elimination of intravenously injected antigen in fed and unfed controls. The reduction of serum antigen is thus likely to reflect reduced absorption, possibly mediated by locally produced antibody. Pigs weaned at 10 weeks old also absorbed antigens and produced an antibody response when introduced to soya; and after three weeks of feeding soya the absorption of antigen was substantially reduced. This latter exclusion was specific for soya as a second novel protein (ovalbumin) was absorbed when introduced to the diet at this time. At six months, pigs no longer absorbed soya proteins when they were introduced to the diet. Furthermore, pigs of this age had serum 'antibody' to soya and other proteins such as keyhole limpet haemocyanin to which they had never been exposed.

Aging↗
PubMed1989

Adjuvant effect of cholera toxin on the mucosal immune response to soluble proteins. Differences between mouse strains and protein antigens.

We examined the effect of orally administered cholera toxin (CT) on the immune response to keyhole limpet haemocyanin (KLH) and ovalbumin (OVA) in high (C57Bl/6 H2b), medium (CBA H2k), and low (BALB/c H2d) responder I-A haplotypes to CT. Mice were fed OVA or KLH on three occasions at 10-day intervals and the effect of simultaneous feeding of CT determined. Isotype-specific antibody levels were assayed in serum samples collected 7 days after the last immunization. Antibody was also measured in the supernatant of gut explant cultures incubated at either 4 or 37 degrees C. Increased antibody levels in cultures kept at 37 degrees C indicated release of local intracellular antibody. Cholera toxin exerted an adjuvant effect on the mucosal response of all three strains to KLH and OVA. Overall, the responses to CT and the second protein were not correlated; we interpret these findings to indicate that while CT had an effect on the mucosal immune system which enhances the immune response to itself and other protein antigens, the final outcome of the response to the second antigen is dependent on differences in the ability of the strains to process, recognize, and respond to a particular antigen.

Adjuvants, Immunologic↗
PubMed1989

Antibody production by the pig colon during infection with Treponema hyodysenteriae.

When 47 pigs were dosed orally with cultures of Treponema hyodysenteriae, 44 (94 per cent) developed swine dysentery. Of those which recovered and were rechallenged, nine of 21 (43 per cent) showed clinical signs, as did one of 10 (10 per cent) challenged on a third occasion. Clinical disease was associated with development of specific IgG, IgA and IgM antibodies in serum and the local production of IgA in gut mucosal tissues. The appearance of antibody was not directly related to protection but rather indicated either prolonged exposure (in the case of serum IgG) or recent exposure to T hyodysenteriae (for secretory IgA). Infection also resulted in the appearance of IgG and IgA memory cells in gut-associated lymphoid tissue. However, these studies indicated that humoral immunity alone is not responsible for the onset of a protective response to T hyodysenteriae in the colon.

Animals↗
PubMed1988

Histochemistry of mucins of pig intestinal secretory epithelial cells before and after weaning.

Two histochemical staining techniques, Alcian blue/PAS and high-iron-diamine/Alcian blue, which differentiated neutral from sulphated and sialylated acid mucins were applied to sections of duodenum, ileum, caecum, colon and rectum from pigs aged one day, 3 weeks and 10 weeks. In each age group, sulphated-acid mucins predominated at all sites, particularly in the large intestine. In both the small and the large intestine, non-sulphated mucins occurred mainly at the bases of the crypts. Neutral mucins occurred in a few goblet cells in crypts and villi, either alone or together with acid mucins; neutral mucins increased away from the bases of the crypts. No changes were noted in the caecum, colon or rectum of pigs one, two, 5 or 13 days after weaning onto a diet containing soya protein. In the small intestine, there was a transient increase in the numbers of goblet cells in the crypts and villi, a relative increase in sulphated and a decrease in non-sulphated acid mucins and a change in the distribution of sulphated mucins in the crypts. No change in proportions of neutral and acid mucins was detected.

Animals↗
PubMed1988

The distribution of mucosal lymphoid nodules in the equine respiratory tract.

Mucosal lymphoid nodules were identified within the equine respiratory tract by an acetic acid fixation technique. Nodules were identified in foetuses from nine months gestational age, and estimates of total and regional nodule populations were made in foetal, neonatal and adult horses. Nodules occurred at specific sites within the tract, which probably relate to areas where inhaled antigens accumulate. The largest populations of nodules occurred in the nasopharynx and larynx, with smaller numbers in the nasal cavity, trachea and bronchi. There was an age-related change in the size of these nodule populations, with an increase in number from late gestation to the neonatal period to early adulthood (up to 5 years of age), followed by a decrease in older adults.

Animals↗
PubMed1988

Use of hyperimmune serum in treatment of endometritis in mares.

Endometritis was induced in four progesterone-treated ovariectomized mares and in two seasonally anestrous mares by intrauterine infusion of Streptococcus zooepidemicus. The bacteria were suspended in phosphate buffered saline (PBS), or in nonimmune or hyperimmune serum. Uterine lavage was performed after 24 h. Significantly fewer (P < 0.05) bacteria were recovered from mares which received hyperimmune serum than from mares which received nonimmune serum or PBS. There was no significant difference between treatment with nonimmune serum or PBS. It is therefore suggested that increasing the availability of specific antibody reduced the severity of intrauterine infection.

Journal Article↗
PubMed1988

Concentrations of immunoreactive leukotriene B4 in uterine lavage fluid from mares with experimentally induced and naturally occurring endometritis.

Acute endometritis was induced in ovariectomized pony mares by infusion of a 1% solution of oyster glycogen. Maximum concentrations of immunoreactive leukotriene B4 in uterine washings coincided with the greatest rate of infiltration of neutrophils into the uterine lumen. Concentrations of immunoreactive leukotriene B4 decreased to basal levels 6 h after infusion and were unaffected by administration of ovarian steroids to ovariectomized mares. Uterine washings from mares with persistent endometritis did not contain significantly different concentrations of leukotriene B4 from genitally normal mares.

Animals↗
PubMed1988

Distribution and ultrastructure of mast cells in the equine respiratory tract.

Mast cells in the equine respiratory mucosa were studied at both light--and transmission electron--microscope levels. Mast cells were identified at all levels of the tract, with the greatest cell density in the nasopharynx. The majority (57 to 94 per cent) of this cell population were located within the connective tissue of the lamina propria. Up to 20 per cent of these cells were associated with the mucosal glandular tissue, whilst small numbers were present within the surface epithelium and in association with nodular lymphoid tissue. In the peripheral lung tissue 20 per cent of the mast cell population was associated with the small airways, 25 per cent with the pleura, and 32 per cent with blood vessels. The fine and ultrastructural features of these mast cells resemble those described in other species, and their granules consist of two types which resemble human mast cells.

Animals↗
PubMed1988

Increased local IgA production in chronic obstructive pulmonary disease.

The immunoglobulin (Ig) content of serum and tracheal lavage fluid was measured in 50 horses suffering from chronic obstructive pulmonary disease (COPD) and 40 control horses. The mean immunoglobulin: albumin ratios of the lavage fluids of both groups were significantly higher than the corresponding values for serum, which indicates significant local production of immunoglobulins in the lower respiratory tract. The IgA: albumin ratio of lavage fluid was significantly higher in diseased compared with normal horses, which implies increased local production of IgA in this disease. The IgG: albumin and IgM: albumin ratios of lavage fluid were not significantly different in the two groups of horses. These results reveal an involvement of the respiratory mucosal immune system in COPD.

Albumins↗