The effect of cyclophosphamide on suppressor cells in guinea pigs.

Treatment of guinea pigs with cyclophosphamide is known to deplete lymphoid tissues, although its effect on delayed hypersensitivity is varied. Experiments were conducted in which suppressor cell activity was studied in vitro in association with histological changes in different lymphoid tissues. An inverse relationship existed between the number of thymic lymphoid cells and thymic suppressor cell activity. In the spleens, suppressor cell activity was also observed initially, but its course could not be followed because of increased myelopoietic action.     

The effects of plasma from guinea pigs with tumor on PHA stimulated lymphocyte cultures.

Strain 13 guinea pigs with a transplanted, 3-methylcholanthrene induced fibrosarcoma produced a plasma factor that inhibited PHA induced blastogenesis of lymphocyte cultures from normal and tumor animals. The suppressive activity was not cytotoxic, was not adsorbed from plasma by lymph node cells, and was a noncompetitive inhibitor of PHA activation. The tumor plasma could not inhibit the uptake of [³H]thymidine if added during the period of maximal DNA synthesis, which suggested that the suppressive factor acts most effectively on metabolically resting cells. This nonspecific suppressive factor may represent an important mechanism for allowing rapidly progressive tumors to escape immunological destruction.     

Electrophoretic and immunoelectrophoretic studies of sera from normal, tuberculous, and noninfected tuberculin-sensitive guinea pigs

Dardas, T. J. (Michigan State University, East Lansing), and V. H. Mallmann. Electrophoretic and immunoelectrophoretic studies of sera from normal, tuberculous, and noninfected tuberculin-sensitive guinea pigs. J. Bacteriol. 92:76-81. 1966.-Normal guinea pig serum was separated into seven fractions by electrophoresis on cellulose acetate membranes. Thirty antigens were found by immunoelectrophoresis: albumin, 6 alpha(1) globulins, 11 alpha(2) globulins, 6 beta(1) globulins, 5 beta(2) globulins, and gamma globulin. Hyper-alpha(2)-globulinemia was detected in sera from guinea pigs 14 days after inoculation with viable virulent Mycobacterium bovis. An additional alpha(2) globulin, not demonstrable prior to infection, was detected concomitantly with the hyper-alpha(2)-globulinemia by immunoelectrophoresis. The additional alpha(2) globulin was tentatively named alpha(2)-T. It persisted until the death of the guinea pigs. Neither hyper-alpha-globulinemia nor the alpha(2)-T antigen was detected by cellulose acetate electrophoresis and immunoelectrophoresis of sera from guinea pigs sensitized with heat-killed M. bovis. Both changes were due to the disease, not to delayed sensitivity alone.     

Studies on coccidiosis in guinea pigs. 2. Epizootiological survey

An epizootiological survey has been carried out on naturally occurring coccidiosis in Hartley guinea pigs (weight, 250g) purchased by the National Institute of Health, Tokyo during the period 1964 to 1982. Coccidial infections in breeding colonies of guinea pigs were observed very frequently in weaned animals but scarcely in adult and suckling animals. Oocysts of Eimeria caviae were detected in 53.8% of the 7,162 fecal samples collected from transportation boxes and coccidiosis occurred in 39% of the 1,461 dead or culled animals obtained during the routine one week quarantine period. In the period 1964 to 1971, particularly high rates of prevalence of oocysts, between 55-86%, and incidence of coccidiosis, between 55-76%, were observed. These rates were clearly reduced in the period 1972 to 1982, with a lower rate of isolation of oocysts ranging from 14-48% and les than 20% incidence of coccidiosis (except in 1981 and 1982). The monthly fluctuation of occurrence rates of oocysts and clinical coccidiosis differed over the period of study. From 1964 to 1971, the high prevalence of oocysts was consistently observed accompanied by a bimodal pattern of incidence of coccidiosis in April (85%) and October (78%). In the period 1972 to 1982, both parameters showed a single peak, for prevalence of oocysts in June (60.7%) and for incidence of coccidiosis in May (45%). Oocysts in feces disappeared in February and March and coccidiosis occurred irregularly in 1981 and 1982.(ABSTRACT TRUNCATED AT 250 WORDS)