The relative proportions of IgG-, IgAand IgM-containing cells in rabbit tissues during experimental trichinosis

Abstract

The relative proportions of IgG, IgM and IgA immunoglobulin-containing cells were determined in the intestinal mucosa, spleen, popliteal lymph nodes and diaphragm of rabbits after a single infection and after hyperinfection with Trichinella spiralis. Staining with pairs of immunofluorescent reagents, specifically reactive with γ, μ or α immunoglobulin heavy chains and labelled with contrasting fluorochromes, permitted direct counting of cells containing two different immunoglobulin classes in a single tissue section. By employing two different pairs of reagents on adjacent sections the relative numbers of cells containing IgG, IgM and IgA were calculated.

The observed cellular distribution of γ, μ and α heavy chains in the rabbit intestinal mucosa corresponded with the reported distribution in the human intestine. A relative increase in IgM-containing cells in the mucosa was observed after early infection with Trichinella, followed by an apparent increase in cells with IgG late in infection and after hyperinfection. The proportion of cells staining for IgA remained uniformly high in the intestine throughout the course of infection.

The proportions of cells containing different immunoglobulin classes in the spleen contrasted with those observed in the intestinal mucosa, particularly with respect to cells containing α chain. IgA cells made up 2–10 per cent of the immunoglobulin-containing cells in the spleen as compared to 80–90 per cent in the intestinal mucosa. Most spleen sections showed an increase in IgM cells late in infection with Trichinella and after hyperinfection. The proportions of immunoglobulin-containing cells in the popliteal lymph nodes generally paralleled those observed in the spleen.

Local cellular infiltration of the diaphragm occurred at the time of larval encystment. Immunoglobulin-containing cells were often prominent and the cellular distribution of immunoglobulin classes resembled that found in the spleen.

The indirect fluorescent antibody technique was employed to detect anti-Trichinella antibody of the three immunoglobulin classes in sera and extracts of the gut of hyperinfected rabbits. Only IgG antibody was detected in gut extracts although both IgG and IgA were demonstrated to be present by Ouchterlony analysis. Both IgG and IgA were demonstrated to be present by Ouchterlony analysis. Both IgG and IgM antibodies were demonstrated in the sera.