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Biomedical subjects

R A Chandler

Publications and source records attributed to R A Chandler.

12 recordsLinked to original sources
PubMed1995

Antibody degradation in wound exudates from blowfly infections on sheep.

Sheep were immunised with ovalbumin and then infected with the sheep blowfly, Lucilia cuprina in order to study immunoglobulin and specific antibody degradation at the wound site. Serum and wound exudates were collected over the infection period and the dry weight and protein content of the exudates were determined. Exudates were analysed by SDS-PAGE and immunoblotting for IgG degradation. Levels of IgG and specific anti-ovalbumin antibodies in the exudates were measured by ELISA. The total weight of exudates increased over the whole period of the infection, while protein content increased in the first 24 h and then remained relatively constant. Immunoglobulin was present 6 h after infection and levels increased with protein content. However, the levels of IgG measured were quite different depending on the secondary antibody used in the ELISA. A monoclonal antibody measured mainly intact IgG while a polyclonal anti-IgG measured intact and degraded IgG. This allowed an estimation that approximately 60% of the IgG in exudates was degraded from 6 h after infection. Assays in vitro showed that L. cuprina larval enzymes degraded sheep antibody. However, measurement of specific anti-ovalbumin levels in exudates suggested that although high levels of antibody were degraded this did not necessarily decrease the level of antigen binding. As a result, IgG degradation may assist and not hinder vaccine development by allowing antibody fragments to penetrate the peritrophic membrane and access gut cell antigens.

Animals↗
PubMed1992

The sheep antibody response to repeated infection with Lucilia cuprina.

The specific serum antibody responses of sheep exposed to 10 consecutive infections of L. cuprina have been analysed by enzyme-linked immuno-sorbent assay and immunoblotting using monoclonal antibodies specific for sheep immunoglobulin isotypes. Recognition of a number of larval excretory-secretory products by IgM antibodies appeared to be non-specific. IgG1 was the major antibody class stimulated by the infection protocol and marked increases in antibody to specific excretory-secretory antigens were observed. Three molecules of 35, 30 and 25 kDa were particularly recognized although the extent of recognition of these molecules varied considerably between individual sheep serum. A pooled serum composed of sera collected after five to seven infections significantly inhibited larval growth in in vitro cultures when compared to a sera pool consisting of sera collected both prior to infection and after infections 1 and 2. The degree of inhibition was greater when serum with high specific antibody titre was used.

Animals↗
PubMed1992

Hypersensitivity responses and repeated infections with Lucilia cuprina, the sheep blowfly.

Sheep repeatedly infected with L. cuprina at 2- but not 4-week intervals developed partial resistance to infection after five infections, as measured by larval recovery. However, resistance did not persist for more than three infections. Skin weal responses were measured after injection of larval products simultaneously with each infection. The only correlation between weal size and larval recoveries occurred at infection 1 and indicated a relationship between skin sensitivity and innate rather than acquired resistance. The results suggest that resistance to L. cuprina can develop after repeated infections but that it is short lived and requires frequent larval exposure. A role for hypersensitivity responses was not confirmed by the weal responses but was suggested by the size of wound developed per larva recovered.

Animals↗
PubMed1990

Tryptic and chymotryptic proteases released by larvae of the blowfly, Lucilia cuprina.

Proteases released by larvae of the sheep blowfly have been suggested to have a primary role in wound formation and larval nutrition. Assays were carried out on two larval products to analyse the substrate specificity of these proteases, their abundance and approximate molecular weights. Tryptic and chymotryptic activities were found in both products though there were more chymotrypsin-like enzymes in products from 48 h cultures (CESP) than in product collected direct from 48 h larvae (LESP). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) gels incubated with azocasein showed plaques of major enzyme activity at molecular weights of 20,000 and 26,000 in LESP and at 20,000 in CESP, SDS-PAGE gels, when reacted with peptide substrates showed tryptic activity at 20,000 and 26,000 in LESP, whereas CESP showed only chymotryptic activity at 20,000 and higher molecular weights. The results suggest at least three enzymes, a trypsin and chymotrypsin in LESP, a chymotrypsin in CESP and a tryptic enzyme which is not stable to SDS-PAGE probably in both LESP and CESP. In addition, reactivity with elastase and plasmin substrates suggests the presence of enzymes with general effects on skin substrates and inflammatory pathways.

Animals↗
PubMed1986

Neutralizing antibody in Celebes black macaques recovering from infection with simian acquired immunodeficiency syndrome retrovirus type 2.

Neutralizing antibodies that block the ability of simian acquired immunodeficiency syndrome (SAIDS) retrovirus type 2 (SRV-2) to induce syncytium formation in cultures of Raji cells have been found in the serum of nonviremic Celebes black macaques (Macaca nigra). Serum from Celebes macaques that are viremic have little or no neutralizing activity. The neutralizing antibodies were shown to block viral infectivity. The group of monkeys with neutralizing antibodies in their serum exhibited a dramatic improvement in their health from 1982 to 1984. The correlation of neutralizing antibodies with clinical improvement suggests that neutralizing antibodies may play a critical role in limiting the pathogenic effects of SAIDS retrovirus infection and in helping eliminate the infection.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Association of SAIDS/RF-related signs with current or past SAIDS type 2 retrovirus infection in a colony of Celebes black macaques.

The 83 members of the Celebes black macaque (Macaca nigra) colony were screened for viremia with simian acquired immunodeficiency syndrome (SAIDS) type 2 retrovirus and antibodies against the retrovirus. On the basis of this screening, the Celebes colony was divided into four groups: retrovirus-positive/seropositive (virus+/Ab+); retrovirus-negative/seropositive (virus-/Ab+); retrovirus-positive/seronegative (virus+/Ab-); and retrovirus-negative/seronegative (virus-/Ab-). Monkeys in the virus+/Ab+ group displayed more major clinical signs and required medication more times than monkeys in the other groups. In contrast, monkeys in the virus-/Ab- group had fewer health problems than monkeys in the other groups. The five monkeys that had surgically confirmed retroperitoneal fibromatosis (RF), palpable abdominal masses, or both, were in the virus+/Ab+ group. Some of the monkeys in groups with current or past retrovirus infection were well clinically. There were no statistically significant differences in the mitogen reactivities of mononuclear cells obtained from monkeys of the different groups.

Acquired Immunodeficiency Syndrome↗
PubMed1976

An evaluation of selective broths based on the bi-selenite ion and on hypertonic strontium chloride in Salmonellae detection in egg products.

Of the 104 isolations of Salmonella sp. from egg pulp, 97 were obtained from strontium chloride M broth, 42 from strontium selenite broth and 57 from strontium selenite A broth. The results suggest that the first medium may be used more successfully than bi-selenite based media for enrichment and subsequent detection of salmonellae in egg products; however, the growth of S. pullorum was not satisfactory in strontium chloride M broth.

Culture Media↗