Carbohydrates are less antigenic than peptides and this may be the reason for the impaired host immune reaction. This delayed immune response at primary infestation suggested that parasites may induce immunosuppression of the cellular response. Fisher et al. In both studies, poor reactivity of lymphocytes of both naive and infested cattle was noticed. All these data suggest that HA may be the major protein with a suppressive activity on immune system.
Results are for one representative of four.
Each symbol represents one animal. The 6-day blast cultures were incubated with these solutions for 18 hours. The cells were pulsed with 1 mCi tritiated thymidine for the last 6 hours . Immunosuppression mediated by HA of in vitro mitogen-induced proliferation is at least due to increased PGE2 release by monocytes and subsequent inhibition of IL2 production. The effect of HA may be due to interaction with molecules implicated in the PGE2 regulation pathway, but HA can also act directly on monocytes and lymphocytes.