NECATOR-AMERICANUS IN INBRED MICE - EVIDENCE IN SUPPORT OF GENETICALLY-DETERMINED DIFFERENCES IN THE CELLULAR IMMUNE-RESPONSE TO A PRIMARY INFECTION

The blood and broncho-alveolar leucocyte (BAL) responses, to a primary Necator americanus infection, were studied in male BALB/c and NIH mic e. Following percutaneous infection, a significant blood leucocytosis occurred in both the BALB/c and NIH strains. The peak response occurre d, in both strains, on day 10 p.i. and this was reflected in the eosin ophil response which peaked at the same time-point. The change in bloo d eosinophil numbers, as a result of infection, was found to be the gr eatest recorded for any cell type. In BALB/c mice, however, infection elicited a significantly more intense total leucocyte, lymphocyte and eosinophil response than in NIH mice. In contrast, the BAL response wa s more intense in the NIH strain. Peak BAL responses were observed bet ween days 12 and 16 p.i., in both strains, and the change in broncho-a lveolar eosinophil numbers, as a result of infection, was found to be the greatest recorded for any cell type. The relationship between the observed leucocyte responses and resistance to the migrating larvae of a primary infection is discussed.