Immunogenicity of subcellular fractions of Brucella abortus: measurement by in vitro lymphocyte proliferative responses.
Five groups of heifers were immunized with various subcellular fractions of Brucella abortus and tested for their responsiveness in lymphocyte proliferative responses in vitro. The five subcellular fractions used as immunogens were: (1) a mixture of recombinant outer membrane proteins fused to Escherichia coli beta-galactosidase, (2) a mixture of outer membrane proteins BaomI, BaomIIB1, and BaomIII1, (3) a mixture of outer membrane proteins 7.5 kDa and 8.8 kDa, (4) a complex of smooth lipopolysaccharide and proteins, and (5) a complex of outer membranes and peptidoglycan (OM-PG complex) from a rough strain. All immunogens were emulsified in adjuvant and administered twice at a 61-day interval. Two other groups of cows were included; one immunized with strain 19 and the other with adjuvant only. Strain 19 and the rough OM-PG complex induced responsiveness in lymphocyte proliferation assays in a high percentage of immunized cows. The smooth lipopolysaccharide-protein complex induced responsiveness in fewer cows. The lowest frequencies of responding cows were found in groups that received either recombinant proteins or purified protein mixtures. Based on these results, we concluded: (1) cellular immunity, as measured by in vitro lymphocyte proliferative responses, can be induced with subcellular fractions of B. abortus and (2) the more complex the immunogen, the greater the frequency of responding cows.
Smith
R
R
Department of Veterinary Pathology, Texas A&M University, College Station.
Adams
L G
LG
Ficht
T A
TA
Sowa
B A
BA
Wu
A M
AM
D000704:Analysis of Variance; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D002003:Brucella abortus / Q000276:immunology*; D002417:Cattle / Q000276:immunology*; D016009:Chi-Square Distribution; D007111:Immunity, Cellular / Q000276:immunology; D007114:Immunization / Q000662:veterinary; D008213:Lymphocyte Activation / Q000276:immunology; D011897:Random Allocation; D013347:Subcellular Fractions / Q000276:immunology
D000942:Antigens, Bacterial