The In Vitro Action of Immune Serum on the Juveniles of the Nematode, Oesophagostomum columbianum (Curtice, 1890) Stossich, 1899

Abstract

1. A precipitate was formed at the oral opening, excretory pore and anal opening of the fourth stage juveniles of O. columbianum in the presence of immune serum in vitro, causing their immobilisation and subsequent death in large numbers. The precipitates failed to appear on these juveniles in normal serum or in saline; nor did they appear on the third stage juveniles on incubation in immune sera. Apparently the excretory-secretory products of the fourth stage juveniles of O. columbianum serve as antigen and play an important role in the stimulation of antibodies in the host.2. Inactivation of the immune serum did not destroy the precipitin type of antibody, nor was it affected when the immune animals had been treated with cortisone.3. Immune serum from animals receiving multiple infections showed a higher antibody titre.4. The possible way in which the antibody acts on the fourth stage juveniles, causing their immobilisation and subsequent death, is discussed.

Oesophagostomum columbianum: gamma-irradiated third-stage larvae for immunization in lambs

“…The highly significant differences observed in the percentage establishment of nodules between the immunized and control groups, and significantly high percentage of nodules from immunized animals containing histotrophic stages confirm our earlier findings that formation of nodules and arrested development of larvae within them may be one of the manifestations of acquired resistance (DHAR & SINGH, 1968;SHARMA & DHAR, 1979). As acquired resistance to 0. columbianum under natural and experimental conditions is always accompanied by the formation of nodules in the intestinal wall and in extra-intestinal sites (MONNIG, 1934; SARLES, 1944; SHELTON & GRIFFITHS, 1968; DHAR & SINGH, 1970;SHARMA & DHAR, 1979), all vaccines, whether viable or nonviable, that may be used for immunoprophylaxis against 0. columbianum in sheep and other animals are likely to lead to nodule formation.…”

“…Similar immunological unresponsiveness has been shown in three-month-old lambs against Trichostrongylus colubriformis (see GREGG et al, 1978). Although development of an acquired resistance in animals to nodular worms has been demonstrated (MONNIG, 1934;SARLES, 1944;ROBERTS et al, 1962;DHAR & SINGH, 1968), it has not been found possible to stimulate more than a marginal protective immunity in lambs and kids aged up to three months following immunization with irradiated larvae (DHAR & SINGH, 1970;SHARMA & DHAR, 1979). This led us to speculate whether young animals showed immunological un-responsiveness also to 0. columbianum but our present findings, which show between 64-7 and 71-9% protection in the immunized lambs, suggest that this may not be so.…”

“…Fresh third-stage larvae for the vaccination work were y-irradiated at 40-kR from a 60 Cobalt source (Gamma chamber 900, Isotopes Division, BARC, Trombay, Bombay, India) installed at our laboratory at Srinagar, Kashmir. The methods used for irradiation of larvae, vaccination, challenge and postmortem examination of animals, and examination of nodules for histotrophic stages of O. columbianum were as described previously (DHAR & SINGH, 1968;SHARMA & DHAR, 1979).…”

Effect of Irradiation on the Infective Stage Larvae of the Nematode, Oesophagostomum columbianum and their Use as a Vaccine

“…In the present study irradiation at 40,000 r markedly reduced the pathogenicity of infective larvae of 0. columbianum. Thus, 6000 non-irradiated larvae of this species when given to a susceptible host proved pathogenic (Dhar, 1965), but 5000 irradiated larvae produced only mild clinical signs of the disease. Signs of disease observed during immunisation were, however, more distinct in kids exposed to 4000 and 5000 irradiated larvae than in the kid given 2000.…”

“…The source of kids and 0. columbianum infective larvae, the general methods of infecting the animals, counting juveniles and eggs, postmortem examination, as well as the care and maintenance of experimental animals have been described elsewhere (Dhar & Singh, 1968).…”