The Effect of Antibody on the Permeability Control of Larval Taenia taeniaeformis

Abstract

The in vitro effects of immune rat serum on larval Taenia taeniaeformis were investigated. With the use of isotopically labeled glucose, sucrose, and methionine, an alteration in tegumentary membrane permeability was detected. Also, leakage of internal methionine was enhanced after treatment with immune rat serum. The activity was present in the gamma globulin fraction and was complement-dependent. The in vitro activity of immune serum was removed by absorption with either a saline extract of the larvae or their excretory-secretory products. Absorption of immune rat serum with these antigens also removed at least one immunodiffusion precipitin band. The uptake of sucrose, normally excluded by larvae, supports the interpretation that antibody-antigen reactions physically alter membrane structure. The alteration of larval T. taeniaeformis permeability by immunoglobulin seems similar to the effects of antibody on ascites tumor cells. Previous investigations (Campbell, 1938; Kraut, 1956) on the acquired immunity of rats to larval Taenia taeniaeformis indicated the occurrence of two qualitatively different protective antibodies. One, appearing early in the infection, was found to be most effective on the early or invasive stage of the parasite. A later antibody, distinguishable from the other by its failure to be absorbed with larval homogenate, exerted its protective action against the already encysted larvae. The hypothesis was suggested (Campbell, 1938) that this "late" antibody had an antimetabolic function. Unfortunately, the knowledge of the biochemical and ultrastructural effects of antibody on parasites is rudimentary. This investigation had as its purpose to explore some of the in vitro effects of antibody on larval T. taeniaeformis and to develop techniques to measure certain biochemical alterations. An important finding was the antibody-induced alteration of larval uptake and loss of isotopically labeled compounds. MATERIALS AND METHODS Origin and maintenance of parasite The strain of T. taeniaeformis used in this research was obtained from Dr. T. von Brand of the National Institutes of Health, Bethesda, Maryland. The adult worms were grown in mature cats maintained in the laboratory. The cats were purged Received for publication 26 January 1971. * Postdoctoral Trainee, USPHS Training Grant No. 5, T01-AI00331-03. These studies have also been supported by NIAID Grant AI00884. Present address: Naval Medical Research Institute, NNMC, Bethesda, Maryland 20014. with arecoline hydrobromide when gravid proglottids were required. The proglottids were teased apart and liberated eggs were washed once in tap water, concentrated by centrifugation and stored at 4 C until needed. For exposure of Holzman rats the egg concentration was determined with a Scott hookworm counting chamber, and adjusted with water if necessary. The eggs were introduced into the stomach by oral intubation with a blunt needle and syringe.