Published online by Cambridge University Press: 18 November 2009
Antibodies were demonstrated in the sera of rabbits experimentally infected by mouth with the eggs of A. suum.
An alcoholic extract of freeze-dried ovaries, oviducts and uteri of adult female Ascaris worms was used as an antigen in the complement fixation test, and a polysaccharide fraction and a saline extract of whole worms were used as antigens in the conglutinating complement absorption test.
In all rabbits the pattern and nature of the antibody response was similar using the three different antigens. When the saline extract antigen was used in the C.C.A.T., antibodies were detected earlier, and titres were recorded higher, than when other systems were used. The degree of response was proportional to the size of the infective dose. Circulating antibody first appeared between the third and eighth days of infection. The highest concentration of serum antibody was reached between the eighth and twenty-first days, and in those animals which received large doses the maximum response occurred about the third week. By repeated twice-weekly infection antibody was demonstrated in the serum for 114 days.