Heligmosomoides polygyrus (= Nematospiroides dubius): Humoral and intestinal immunologic responses to infection in mice

Abstract

Measurements of serum IgG 1, IgG 2a, IgM, and IgA levels and antibody titers in these immunoglobulin classes were made at intervals after initial infection and challenge infection of mice immunized by two or three previous infections. Identical measurements were made on the content of the small intestine in mice which had been exposed to the same infection schedule. Sections of small intestine taken after initial infection and challenge infection were examined by the fluorescent antibody technique for changes in populations of immunoglobulin-containing cells and by routine histologic procedures for histopathologic changes. In serum, only IgG 1 was consistently increased after initial infection, and antibody in IgG 1 was detected within the first 2 wk of infection. In immunized animals, only IgG 1 and antibody of this class always responded to challenge infection, although antibody in other immunoglobulin classes was detected. IgA concentration of the intestinal content did not differ significantly after initial infection or challenge infection of immunized mice. Immunized mice had about twice the IgG 1 concentration in intestinal content as singly infected animals. No intestinal antibody was detected after initial infection; only IgG 1 antibody was detected in the intestinal content of immunized and challenged mice. Cell infiltrates in the intestinal mucosa and submucosa of immunized animals contained numerous IgG 1-containing cells. Mast cells and globular leukocytes were observed in the intestine of immunized animals.