Responses to polyvinyl pyrrolidone and pneumococcal polysaccharide in protein-deficient mice

Indirect haemagglutination titres induced by polyvinyl pyrrolidone (PVP) or pneumococcal polysaccharide Type III (S111) were determined in mice maintained on a 4% albumin diet from weaning and normally-fed littermates. Responses to PVP, given intravenously (i.v.) or intraperitoneally (i.p.), were elevated by protein-deficiency at low antigen doses and increasingly depressed at high doses. Increases in the duration of protein-deficiency generally improved these responses. The persistence of tolerance was reduced by protein-deficiency and priming was evident in both groups when tolerance was broken. The low protein diet depressed responses to moderate doses of S111 given i.p. to C57Bl mice, but such responses were normal in BALB/c mice and in C57Bl mice injected i.v. High doses of S111 (i.p., i.v.) elicited poor responses in deficient mice. These findings are discussed in relation to previous studies using other antigens, with a view to elucidating mechanisms responsible for the effects of protein-deficiency.