Submitted to: American Association of Veterinary Parasitologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: March 24, 1998
Publication Date: N/A
Development of protective immunity to Ostertagia ostertagi is slow and incomplete in spite of strong immunological changes induced at the local site of infection. In contrast Haemonchus placei which also colonizes the abomasum induces rapid and efficient protective immunity in field situations. In the present study differences in local immune responses after either a primary or a challenge infection with O. ostertagi or H. placei were studied. As shown in previous studies no differences in the number of worms developing after a challenge infection with O. ostertagi were noted. Changes in both cytokinine and cell surface markers in the local lymph nodes and in the mucosa were in agreement with previously published data. Histological studies of the mucosa showed large increases in the number of eosinophils(EO) and decreases in globular leucocytes(GL). Primary and challenge H. placei infections were clearly different in all parameters when compared to O. ostertagi. Animals with either a primary o challenge infection showed smaller abomasal lymph nodes, but higher number of intra-epithelial (IEL) and lamina propria(LPL) lymphocytes. Histologically the number of EO present in the mucosa decreased after challenge, but the number of GL and mast cells was strongly increased. H. placei primary and challenged animals also showed significantly smaller amounts of IFN-g mRNA in the LPL, and after challenge there was a downregulation of the inflammatory cytokines IL10, TGF-beta and TNF-alpha.