Lymphocyte reactivity to antigens of Haemonchus contortus in antigen-inoculated and H contortus-naive lambs.
Lambs were inoculated during either fetal or early neonatal life with antigens of Haemonchus contortus (HcAg) third-stage larvae, or ovalbumin (OVA), or were left untreated. By the time lambs were 4 weeks old, blood lymphocytes from all of them responded to HcAg. This was evident in all lambs, regardless of the previous inoculation regimen, although higher response was seen in HcAg-inoculated lambs, compared with naive lambs. Only lambs inoculated with OVA had OVA-specific lymphocyte activity. In HcAg-naive lambs, the maximal HcAg lymphocyte response was observed between the ages of 5 and 25 weeks, with gradual decrease thereafter. In vitro detection of HcAg-reactive lymphocytes was affected by antigen concentration and presence of plasma. Plasma inhibited HcAg-reactive lymphocytes from all lambs at high in vitro antigen concentration and completely abrogated the response in H contortus antigen-naive lambs.
Torgerson
P R
PR
Department of Clinical Veterinary Medicine, University of Cambridge, England.
Lloyd
S
S
D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D006188:Haemonchiasis / Q000276:immunology / Q000662:veterinary*; D006189:Haemonchus / Q000276:immunology*; D007111:Immunity, Cellular; D008137:Longitudinal Studies; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000276:immunology*; D010047:Ovalbumin / Q000276:immunology; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology*
D000947:Antigens, Helminth; D010047:Ovalbumin