Effects of cyclophosphamide on the immune response of pigs to Salmonella cholerae-suis var kunzendorf.
The effects of the immunosuppressive agent cyclophosphamide (CY) on the immune response of pigs given IM challenge inoculations of a moderately virulent strain of Salmonella cholerae-suis var kunzendorf were examined. Five groups of Yorkshire-cross pigs (approx 6 kg) were given Salmonella, CY, or both at various times after the 1st of a series of doses of CY was given. The drug was administered subcutaneously in 3 doses, 2 days between doses, at a rate of 20 mg/kg of body weight. Cyclophosphamide was observed to produce significant numerical decrease of circulating leukocytes, especially the polymorphonuclear neutrophils. Circulating lymphocyte numbers were reduced to 40% to 60% of base-line values. Pigs (group 4) given 3 x 10(6) S cholerae-suis IM at the time the initial CY dose was given were clinically ill during days 6 to 12; 2 of the 5 pigs died. In contrast, pigs (group 5) given 3 x 10(6) S cholerae-suis at the time of the 3rd dosing with CY did not become clinically ill until 10 days later. A significant increase in antibody titer to S cholerae-suis was delayed in this latter group beyond that of the groups of pigs (group 4) inoculated on the 1st dosing with CY and of pigs (group 6) not given CY. A significant and prolonged increase in mean rectal temperature was observed in those pigs challenge inoculated at the time of the initial CY dose. Pigs also were sensitized to Mycobacterium avium 2 weeks before CY administration. Delayed hypersensitivity reactions were depressed in pigs treated with CY at the time of testing.
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA 50011 USA.
R W
RW
Griffith
T T
TT
Kramer
C
C
McRill
D000818:Animals; D003520:Cyclophosphamide / Q000494:pharmacology*; D006968:Hypersensitivity, Delayed; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D009162:Mycobacterium avium / Q000276:immunology; D012475:Salmonella / Q000145:classification / Q000276:immunology*; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000382:microbiology*; D013552:Swine; D013553:Swine Diseases / Q000276:immunology / Q000382:microbiology*
D007166:Immunosuppressive Agents; D003520:Cyclophosphamide