Passive protection with cells or antiserum against Nippostrongylus brasiliensis in the rat

Abstract

Rats can be passively protected against N. brasiliensis either with antiserum or with cells. Only some pools of antiserum (15 of 48 pools) and a few batches of cells (three of 11 batches) were protective.Protective activity was found in serum taken after one infection as frequently as after several infections and gave the same degree of protection. This suggests that second and subsequent infections do not stimulate an anamnestic increase in protective antibodies in the circulation.Serum and cells taken from the same rats were unrelated in their protective capacity; sometimes serum protected when the cells were ineffective and the reverse also occurred.Cells transferred from the spleen, peritoneal cavity or mesenteric lymph nodes were capable of initiating reagin formation, irrespective of their ability to protect against N. brasiliensis.When protection was achieved with transferred cells, the parasite life-cycle was shortened by only 1–2 days.We have found no evidence that a delayed mechanism of the homograft type is concerned in immunity to N. brasiliensis in the rat.We thank Miss W. D. Griffiths and Mr A. J. Edwards for their willing assistance. The statistical analysis was kindly done for us by Miss M. V. Mussett of the Statistics Department at our Institute.