Antibody response to antigens distinct from smooth lipopolysaccharide complex in Brucella infection

Abstract

The smooth lipopolysaccharide complex of the outer surface of smooth Brucella abortus cells is believed to be the antigenic component involved in serological tests routinely used for the diagnosis of brucellosis. Sera from cattle vaccinated or infected with B. abortus generally contain antibody directed toward the smooth lipopolysaccharide complex. The brucella organism contains a large number of other antigenically distinct components. The biological significance of some of these antigens has been demonstrated by showing that sera from infected cattle have precipitins to these components. These sera revealed up to seven distinct lines in immunoelectrophoresis with a protein-rich antigen mixture prepared from rough strain B. abortus 45/20, whereas sera from strain 19-vaccinated cattle did not reveal these lines at 4 or more months after vaccination. Monospecific antisera were prepared against six antigens in this mixture, and the purification of two of them by antibody affinity chromatography is described. tion of cells with hypertonic NaCi as described by Jones et al. (14) or by sonic disruption as described by Hinsdill and Berman (13).

Localization of brucella antigens that elicit a humoral immune response in Brucella abortus-infected cells

“…Brucella organisms contain a large number of antigenically distinct components, including the smooth lipopolysaccharide (LPS) of smooth virulent cells and the rough LPS of rough organisms (7,13). Sera from Brucella abortus-infected or vaccinated bovines generally contain antibodies directed against the smooth LPS complex of the outer surface of smooth B. abortus cells, as well as antibodies directed against nonsmooth LPS antigens, which can be extracted from rough strain B. melitensis B.115, B. abortus strain 19 (G. Schurig, unpublished data), and B. abortus rough strain 45/20 (13). Seven of these nonsmooth LPS antigens were described by Schurig et al (13) according to their electrophoretic mobility and reactivity with sera from B. abortus-infected and strain 19-vaccinated animals.…”

“…Sera from Brucella abortus-infected or vaccinated bovines generally contain antibodies directed against the smooth LPS complex of the outer surface of smooth B. abortus cells, as well as antibodies directed against nonsmooth LPS antigens, which can be extracted from rough strain B. melitensis B.115, B. abortus strain 19 (G. Schurig, unpublished data), and B. abortus rough strain 45/20 (13). Seven of these nonsmooth LPS antigens were described by Schurig et al (13) according to their electrophoretic mobility and reactivity with sera from B. abortus-infected and strain 19-vaccinated animals. The location of the nonsmooth LPS antigens within the brucella organisms, as well as the role of the immune response to them, is unknown.…”

“…Antigen extracts were obtained from B. abortus strain 45/20 cells which had been grown in a fermentor at the National Animal Disease Center, U. S. Department of Agriculture, Ames, Iowa. Before antigen extraction, cells were treated with acetone as described before (13), washed twice in distilled water, and lyophilized. Antigenic preparations were extracted from the acetone-treated cells with hypertonic NaCl or from sonicates of these acetone-killed cells (2).…”

“…Antigenic preparations were extracted from the acetone-treated cells with hypertonic NaCl or from sonicates of these acetone-killed cells (2). The antigenic preparations contained antigens Al, A2, and A4 described previ-ously (13), and antigen A5 to be described here. Au four antigens are also detectable in extracts of B. abortus strain 19 cells (Schurig, unpublished data).…”

“…(i) Anti-strain 45/20 extract antiserum. Several New Zealand white rabbits were injected subcutaneously with the antigenic, hypertonic NaCl extract of B. abortus strain 45/20 incorporated in Freund complete adjuvant as described before (13). The sera from these rabbits were designated multispecific sera.…”