Differences in susceptibilities of the lymphogranuloma venereum and XXXX biovars of @entity11739 to neutralization by immune sera.

@entity1 @entity11738 @entity19 @entity11739 @entity10560
Sera from seven @entity1 from whom a @entity11739 serovar L2 strain was isolated were tested in vitro for their ability to neutralize the infectivity of this organism. In one @entity1 an inguinal lymph node was culture positive, whereas the remaining six @entity1 had positive rectal biopsies. Sera from four of the @entity1 , including the @entity1 with the lymph node isolate, failed to neutralize serovar L2(434). In addition, the homologous strain recovered from the inguinal lymph node was available and was resistant to neutralization by the homologous sera. However, the same sera effectively neutralized a @entity11738 serovar, E(Bour). All four sera had inclusion immunofluorescent-antibody titers to @entity11739 serovar L2 of 2,048 to 16,384 and microimmunofluorescent-antibody titers to the lymphogranuloma venereum biovar were equal or higher in all cases than to the 12 serovars of the @entity11738 biovar. The three remaining sera, while neutralizing the infectivity of the L2 strains tested, neutralized serovar E to a greater extent. These sera had the same inclusion immunofluorescent antibody titers as the sera that failed to neutralize serovar L2. To see whether this difference in the sensitivity of the biovars toward neutralization could be characterized, sera were obtained from @entity19 immunized with different doses of both serovars L2 and E. Sera obtained from @entity19 immunized with serovar E were able to effectively neutralize the homologous strain. In contrast, neutralization of the immunizing strain, @entity10560 ), was not seen with sera obtained on days 7, 14, and 21 after immunization from animals receiving 8 x 10(5) and 8 x 10(4) inclusion-forming units of @entity10560 ); however, these same sera neutralized serovar E. However, with a higher immunizing dose of L2 (10(7) IFUs), both E and L2 were neutralized with sera obtained 7 and 14 days after immunization. Therefore, the relative resistance to neutralization by serovar L2 compared with that of serovar E in the @entity19 model was inoculum dependent.
