Immunogenicity of Gonococcal Transferrin Binding Proteins during Natural Infections

Abstract

In this study, we examined the immune response during gonococcal infection to the individual transferrin binding proteins by using a quantitative enzyme-linked immunosorbent assay (ELISA). Recombinant transferrin binding protein A (rTbpA) and rTbpB were purified under nondenaturing conditions for use as ELISA antigens. Sera and secretions from culture-positive individuals were analyzed for antibodies to rTbpA and rTbpB and compared to samples from individuals with no history of gonococcal infection. Although antibodies to both rTbpA and rTbpB were detected in serum, in most cases the antibody levels were not significantly different from those measured in the control population. Also, previous history of gonococcal infection did not increase antibody levels in serum, suggesting the lack of an anamnestic response. Analysis of secretion samples revealed antibody levels that were generally below the limits of detection in our assay. Overall, this study demonstrated a paucity of systemic and local antibody responses to rTbps as a result of natural infection and represents a baseline over which a protective antibody response will have to be generated in order to develop an efficacious gonococcal vaccine.

Gonococcal transferrin binding protein chimeras induce bactericidal and growth inhibitory antibodies in mice

“…4A). The smaller product likely results from a secondary start site within TbpB, as has been demonstrated previously [33]. High molecular mass species were apparent in Western blots using TbpB-and TbpA-specific antiserum (Fig.…”

“…In N. meningitidis, L2 is predicted to be the longest surface exposed structure stretching higher than the outer membrane lipopolysaccharide [46]. This in conjunction with human studies demonstrating the existence TbpA serum-specific antibodies following carriage or infection provide evidence that the L2 epitope is unlikely to be completely hidden in the live cell [33,47].…”

“…For detection of TbpA L2, blots were probed with rabbit antisera raised against purified recombinant TbpA [33]. NB was detected with rabbit antisera raised against recombinant TbpB (kindly provided by Christopher Thomas and P. Frederick Sparling).…”

“…Sera and vaginal washes were assayed for antibodies specific for TbpA, TbpB, or total IgG and IgA (vaginal washes only) as described previously [19,33]. Capture and alkaline phosphatase-conjugated goat anti-mouse antibodies were purchased from Southern Biotechnology Associates (Birmingham, Al).…”

Identification of Regulatory Elements That Control Expression of the tbpBA Operon in Neisseria gonorrhoeae

“…For TbpB detection, membranes were blocked with 5% nonfat dry milk in low-salt Tris-buffered saline. Membranes were probed with primary anti-TbpB polyclonal antibodies (30) and washed with low-salt TBS and 0.05% Tween 20, followed by goat-anti-rabbit alkaline phosphatase-conjugated secondary antibody. All blots were developed using the nitroblue tetrazolium-5-bromo-4-chloro-3-indolylphosphate colorimetric system (Sigma).…”