Antibody and cytokine responses to the cilium-associated respiratory bacillus in BALB/c and C57BL/6 mice.
The cilium-associated respiratory (CAR) bacillus is a gram-negative, gliding bacterium that causes persistent respiratory tract infections in rodents despite histologic and serologic evidence of a marked immune response. To assess humoral immunity and cytokine responses in CAR bacillus disease, 6-week-old female BALB/c and C57BL/6 mice were inoculated intratracheally with 10(5) CAR bacillus organisms. CAR bacillus-specific serum immunoglobulins (immunoglobulin M [IgM], IgG1, IgG2a, IgG2b, IgG3, and IgA) and local pulmonary cytokines (tumor necrosis factor alpha [TNF-alpha], gamma interferon [IFN-gamma], and interleukin-4 [IL-4]) were evaluated by enzyme-linked immunosorbent assay every 7 days for 49 days. BALB/c mice developed CAR bacillus-induced lesions early in the course of disease that became more severe with time. Correlating with increasing disease severity, BALB/c mice had elevations in all antibody isotypes tested, and elevations in pulmonary TNF-alpha, IFN-gamma, and IL-4. C57BL/6 mice developed mild lesions with mild increases in serum IgM, IgG1, IgG2b, and IgG3 levels and minimally detectable IgG2a and IgA. Cytokine perturbations were not detected in C57BL/6 mice. The persistence of infection in BALB/c mice with vigorous serum antibody responses and increased IFN-gamma and IL-4 responses suggests that humoral immunity and T-cell responses are ineffective at preventing CAR bacillus disease. Furthermore, the lackluster antibody responses and undetectable cytokine responses in C57BL/6 mice suggest that humoral immunity and T-cell responses are not critical in resistance to CAR bacillus-induced disease.
Kendall
L V
LV
Department of Veterinary Pathobiology, University of Missouri-Columbia, Columbia, Missouri 65211, USA. lvkendall@ucdavis.edu
Riley
L K
LK
Hook
R R
RR
Besch-Williford
C L
CL
Franklin
C L
CL
D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D006090:Gram-Negative Bacteria / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification; D007075:Immunoglobulin M / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009174:Mycoplasma / Q000302:isolation & purification; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013045:Species Specificity
D000907:Antibodies, Bacterial; D016207:Cytokines; D007074:Immunoglobulin G; D007075:Immunoglobulin M