Activation of complement by hydatid cyst fluid of Echinococcus granulosus

Factors present in hydatid cyst fluid of Echinococcus granulosus were found to interact with complement from several species. This nonimmunologic fixation resulted in the depletion of hemolytically active complement from fresh guinea pig serum, the conversion of human C3 to an electrophoretically faster species and the genration of smooth muscle contracting substances, analogous to anaphylatoxins, in normal rat serum in vitro. Vascular permeability changes were produced in vivo in rats and humans after intradermal inoculation of complement interacting fractions of hydatid fluid. It is suggested that these factors may contribute to the pathogenesis of the shock syndrome which follows intravenous administration of hydatid fluid in normal animals, and to the nonspecificity of immunodiagnostic skin tests for hydatid infection in man and animals.

Uptake of colostral immunoglobulins by the suckling rat

The sequential appearance of immunoglobulins was studied in serum samples from rats during the suckling period. At birth both IgG1 and IgG2 were present, but IgM was not detected until the 7th day and IgA until the 17th day. No intestinal transmission of intact homologous IgA was demonstrable after oral administration of radiolabelled preparations (125I) of either serum or colostral IgA to suckling rats. When 125I labelled IgG 2a+b rat immunoglobulins were given orally there was a selective transport of the slower moving subclass from the gut into the serum. The rat appeared to differ from several other species in which some intestinal absorption of passively transferred IgA by the newborn has been demonstrated. It was suggested that retention of colostral and milk IgA in the intestine may serve to enhance local defense mechanisms in the newborn rat.

Antibody-mediated secondary eosinophilic response to Taenia taeniaeformis in the rat

Normal rats were given intravenous doses of either immune serum or immunoglobulin fractions 24 hr before oral challenge with 1,000 eggs of Taenia taeniaeformis. Total eosinophil counts per mm3 were performed for 3 days prior to and 6 days after challenge. Sensitized rats usually showed sharp peaks of eosinophilia 2 to 6 days after this dose. The pattern of the eosinophilic response was similar to that which occurs after challenge of immune infected rats. The differences in peripheral eosinophil levels in passively immunized and normal rats were statistically significant. Immunoglobulin fractions containing protective IgG2alpha were most effective, but a fraction containing reaginic antibody activity also sensitized rats to give secondary eosinophilic responses. The findings are discussed in relation to the probable contribution of antigen-antibody reactions to the production of secondary eosinophilic responses in experimental cysticercosis.

The immunological response of the rat to infection with Taenia taeniaeformis. V. Sequence of appearance of protective immunoglobulins and the mechanism of action of 7Sgamma2a antibodies

Passive transfer of immunity to Taenia taeniaeformis was achieved with serum taken 14, 21, 49 and 63 days after infection. The protective capacity of serum collected at 14 and 21 days resided in the 7Sgamma2 immunoglobulins and appeared to be partics the infection progressed the range of chromatographic fractions showing protective capacity was extended to all those containing 7Sgamma2 and 7Sgamma1 immunoglobulins. Fractions enriched for gammaM did not confer protection. Immune serum containing 7Sgamma2a antibodies was able to kill developing parasites after they had left the intestine, and the hepatic postoncospheral forms retained their susceptibility to antibody over the first 5 days of growth. After that time they rapidly became insusceptible to antibody both in vivo and in vitro. Susceptibility to antibody-mediated attack was complement dependent. This appears to be the first time that complement has been demonstrated to play a role in immunity to a helminth infection in vivo. This finding is discussed in relation to the phenomenon of cestode parasite survival in immune animals.

The immunological response of the rat to infection with taeniaeformis. IV. Immunoglobulins involved in passive transfer of resistance from mother to offspring

Weanling rats born of mothers infected with Taenia taeniaeformis were found to be passively protected against homologous challenge. Cross-fostering of normal suckling rats onto immune mothers established that passive transfer occurred via the colostrum and milk. Immunoglobulin fractions containing gammaA from immune colostrum were fed to 12-14-day-old rats for 4 days via stomach tube. Significant passive protection against challenge with T. taeniaeformis was achieved with gammaA from one of three colostrum pools. The effect of colostral gammaA preparations on the infectivity of freshly hatched oncopheres of T. taeniaeformis was measured by the intra-intestinal inoculation of immunoglobulin solutions into isolated gut loops containing hatched eggs of the parasite. gammaA from one of three pools of immune colostrum caused a significant reduction in the number of parasites which reached the liver. This appears to be the first time that protective activity against a helminth infection has been achieved with gammaA. A fraction of immune colostrum containing both 7Sgamma1 and 7Sgamma2 immunoglobulins was found to confer passive protection when inoculated parenterally. In view of the prolonged period of absorption (ca 18 days) of 7S immunoglobulins from the gut by the suckling rat, it seems likely that these antibodies are primarily responsible for the natural passive transfer of protection from mother to young.

Immunoglobulins associated with passive transfer of resistance to Taenia taeniaeformis in the mouse

Mice were found to be protected against Taenia taeniaforMis infection by passive transfer of serum collected from donors 28 days after infection. The protective activity resided exclusively in the first fraction of 7S immunoglobulins eluting from DEAE-cellulose at pH 5.8 with 0.05 M phosphate buffer. This fraction contained 7Sgamma1 and 7Sgamma2 immunoglobulins but no detectable gammaA, gammaM or skin sensitizing activity. Fractions containing 7Sgamma 2 alone were ineffective in passive transfer.