Eosinophil and IgA responses in sheep infected with Teladorsagia circumcincta.

Infections of sheep with the gastrointestinal nematode Teladorsagia circumcincta are characterised by increased concentrations of IgA, eosinophilia and mastocytosis but the interactions between these immune responses are unclear. We investigated the kinetics of the parasite-specific IgA and eosinophil responses in controlled infections in lambs to determine if there were any associations with subsequent worm growth and survival. IgA and eosinophil responses had very similar kinetics and variation in both responses accounted for more of the variation in adult worm length than either trait alone suggesting that IgA and eosinophils interact in regulating the growth of T. circumcincta. Curiously, those animals with higher peak eosinophil responses had longer worms at slaughter emphasising the intriguing complexity of the immune responses to these parasitic infections.

Preparation of B lymphocyte-specific alloantisera by skin implant immunization of cattle.

B lymphocyte-specific antisera were prepared by immunizing cattle on either one or two occasions with a subcutaneous implant of allogeneic skin and subsequently absorbing the antisera with platelets. After absorption 15/26 antisera displayed B lymphocyte-specific activity. Titres against B-enriched cells were 8-64 while residual titres against B-depleted cells were 1-8. In comparison, 3-6 immunizations with allogeneic leucocytes produced antisera of similar peak cytotoxic titres against donor PBL, and after platelet absorption 8/15 antisera displayed B lymphocyte-specific activity. Titres against B-enriched cells were 8-64 while residual titres against B-depleted cells were 2-8. The skin implant method was less time-consuming than the leucocyte immunization method.

Failure to find an association between ocular squamous cell carcinoma and class I antigens of the bovine major histocompatibility system.

We tested 53 cattle with ocular squamous cell carcinoma (cancer-eye) and 53 paired, matched controls for 25 class I antigens of the bovine major histocompatibility system. The most common antigen was W5 which was present in 40% of the animals with cancer-eye and 36% of the controls. There were no statistically significant differences in BoLA antigen frequency between cattle with and cattle without cancer-eye.

BoLA antigens are associated with increased frequency of persistent lymphocytosis in bovine leukaemia virus infected cattle and with increased incidence of antibodies to bovine leukaemia virus.

The association between bovine major histocompatibility system (BoLA) type and persistent lymphocytosis in cattle with antibodies to bovine leukaemia virus was examined by comparing antigen frequencies in cattle with persistent lymphocytosis to controls matched for age, sex, breed and presence of antibodies to BLV. The cattle came from nine dairy herds in south-east Queensland, Australia; six herds were Australian Illawarra Shorthorn (AIS), two herds were Jersey and one herd was Friesian. Antigen W6 and Eu28R were more common in cattle with persistent lymphocytosis than in controls. Antigen W8 was less common in AIS cattle with persistent lymphocytosis. A study of 24 offspring from one sire, heterozygous for W10 and Eu28R, showed that offspring inheriting Eu28R from the sire were significantly more likely to have antibodies to BLV than offspring inheriting the opposing W10 haplotype.