Abstract
Concentrations of each class of serum immunoglobulins and two subclasses of serum IgG immunoglobulins were obtained from a total of 165 Japanese Black cattle which were classified serologically and hematologically into several groups, and from 9 cattle with adult type leukemia. Results revealed no significant differences in the levels of serum immunoglobulins between groups of cattle serologically negative and positive for bovine leukemia virus (BLV) antibodies, and among groups of hematologically negative, suspicious and positive, On the other hand, the serum IgM level tended to be lower in the hematologically positive group than in the other groups, and significantly lower in the leukemic group (p<0.01). The serum IgG and IgM levels in groups of cattle which subsequently became positive for BLV antibody and were divided into 3 groups on the basis of the number of months following conversion (0-3, 3-7 and 7-12 months) showed no significant difference from the levels in their earlier antibody-negative stage. However, the serum IgG and IgM concentrations of a group of antibody-negative cattle which were converted to antibody-positive while they were still in mountainous pastures were significantly lower than those of the negative group of cattle as evaluated by 3 or 4 immunodiffusion or complement fixation tests given over a time course (p<0.01).
