Lipopolysaccharide from Brucella abortus behaves as a T-cell-independent type 1 carrier in murine antigen-specific antibody responses.
In order to determine the carrier nature of lipopolysaccharide from Brucella abortus (LPS-BA) in evoking humoral responses, normal and immunodeficient mice were immunized with trinitrophenyl (TNP)-conjugated LPS-BA (TNP-LPS-BA) and the responses were compared with those to known T-dependent and T-independent antigens. TNP-LPS-BA, like T-independent type 1 (TI-1) antigens such as TNP-BA and TNP-LPS from Escherichia coli (TNP-LPS-EC), generated anti-TNP responses in BALB/c, athymic BALB/c nu/nu, and CBA/N mice. In contrast, N-2,4-dinitrophenyl-beta-alanylglycylglycyl-substituted keyhole limpet hemocyanin, a typical T-dependent antigen, was not immunogenic in athymic mice, and TNP-Ficoll (T-independent type 2) was ineffective in eliciting humoral responses in CBA/N mice. These results indicate that LPS from B. abortus acts as a TI-1 carrier in generating antibody responses. In C3H/HeJ mice, TNP-LPS-BA generated higher-titer immunoglobulin G1 (IgG1), IgG2a, and IgG2b anti-TNP antibodies than TNP-LPS-EC. Compared with those from BALB/c mice, pure resting B cells isolated from C3H/HeJ mice exhibited a 30-fold lower proliferative response to LPS-EC, whereas the LPS-BA response was reduced to a lesser extent (5-fold). This suggests that the disparity observed in antibody titers was due to different abilities of LPS from B. abortus and E. coli to stimulate C3H/HeJ B cells. The ability of LPS from B. abortus to act as a carrier in generating humoral immune responses indicates that LPS-BA can be substituted for whole B. abortus organisms in vaccine development.
Betts
M
M
Laboratory of Cell Biology, U.S. Food and Drug Administration, Bethesda, Maryland.
Beining
P
P
Brunswick
M
M
Inman
J
J
Angus
R D
RD
Hoffman
T
T
Golding
B
B
D000818:Animals; D000917:Antibody Formation; D000955:Antigens, T-Independent / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology*; D002003:Brucella abortus / Q000276:immunology*; D005260:Female; D008070:Lipopolysaccharides / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D008819:Mice, Nude; D009578:Nitrobenzenes / Q000276:immunology; D011112:Polymyxin B / Q000494:pharmacology
D000955:Antigens, T-Independent; D008070:Lipopolysaccharides; D009578:Nitrobenzenes; D011112:Polymyxin B