In vitro transformation of lymphocytes from blood and milk of cows with subclinical paratuberculosis.
Lymphocytes from blood or milk of 12 cows were evaluated in vitro for the lymphocyte's capability to proliferate in response to mitogens (phytohemagglutinin-A, concanavalin A, and pokeweed mitogen) and to an antigen prepared from Mycobacterium paratuberculosis (purified protein derivative, PPD-J). Responses of 4 control cows were compared with those of 4 cows subclinically infected with M paratuberculosis and with 4 apparently noninfected herdmates. Blood lymphocytes or milk lymphocytes from control cows had no detectable responses to PPD-J. Blood lymphocytes from infected cows had significant (P less than 0.05) responses to PPD-J, but milk lymphocytes from these cows did not. Conversely, milk lymphocytes from apparently noninfected herdmate cows had significant (P less than 0.05) responses to PPD-J, but blood lymphocytes from these cows did not. There were no significant differences in the responses of blood lymphocytes from control, noninfected, or infected cows to the mitogens. However, milk lymphocytes from infected cows had significantly (P less than 0.05) lower responses than did lymphocytes from the milk of control or noninfected cows to all mitogens. The decreased responsiveness of milk lymphocytes from cows subclinically infected with M paratuberculosis may indicate that immunocompetency of the mammary gland was altered.
D000818:Animals; D002417:Cattle; D004261:DNA Replication; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000382:microbiology; D005260:Female; D007074:Immunoglobulin G / Q000032:analysis; D008213:Lymphocyte Activation; D008892:Milk / Q000276:immunology*; D009161:Mycobacterium / Q000302:isolation & purification; D010283:Paratuberculosis / Q000276:immunology* / Q000382:microbiology; D013936:Thymidine / Q000378:metabolism
D007074:Immunoglobulin G; D013936:Thymidine