Parameters affecting the enzyme-linked immunosorbent assay of immunoglobulin G antibody to a rough mutant of Salmonella minnesota.

An enzyme-linked immunosorbent assay was developed to detect rabbit immunoglobulin G antibodies against purified lipopolysaccharide of the rough Re mutant of Salmonella minnesota. The time necessary for each step was investigated, and this resulted in a test that could be completed in 1 working day. Serial dilutions of rabbit sera drawn throughout immunization with the Re mutant revealed an elimination of the prozone effect upon prolonged immunization. We interpret this to demonstrate an increase in immunoglobulin G affinity for the lipopolysaccharide on prolonged immunization. We propose that the enzyme-linked immunosorbent assay prozone effect be investigated for use as a measure of antibody affinity.

Studies on the relationships between serum bactericidal activity and uncomplicated genital infections due to Neisseria gonorrhoeae.

This report concerns the relationships between patients' uncomplicated genital infections due to Neisseria gonorrhoeae and the bactericidal activity of their sera against their infecting organisms. Forty isolates of N. gonorrhoeae and 91 serum samples were obtained from 23 patients with their first or repeated gonococcal infections. Of 32 sera obtained at the time of infection, 14 (44%) were bactericidal for the infecting strains. Of convalescent-phase sera from 27 infections, 12 (44%) were bactericidal; 22%-33% of convalescent-phase sera had increased bactericidal activity when compared with acute-phase sera or sera obtained before infection. Eleven patients developed 17 new infections after sera and negative cultures were obtained; in six (35%) the previously obtained sera were bactericidal but did not prevent infection.

Serum bactericidal action and activation of the classic and alternate complement pathways by Neisseria gonorrhoeae.

In order to more fully understand the host defense mechanisms against gonococcal infections, we decided to define the role of the classic and alternate complement pathways in gonococcal BA. Sera and infecting isolates were collected from several patients with genital and disseminated gonococcal infections. Sera from two never-infected subjects and a hypogammaglobulinemic patient were also collected. Sera from patients with genital gonorrhea and never-infected controls demonstrated marked BA for gonococci after 30 min incubation. Chelation of these sera with MgEGTA delayed the expression of BA. Consumption of C3, but not C4, was observed in chelated samples. BA could not be demonstrated in any of the sera from DGI patients or the patient with hypogammaglobulinemia. Aliquots of fresh and chelated hypogammaglobulinemic serum to which IgM or IgG antigonococcal antibodies were added showed marked BA by 30 and 60 min, respectively. Absorption of chelated serum with a serum-sensitive isolate eliminated the previously observed delayed BA. The findings suggest that gonococcal serum BA is primarily associated with activation of the classic complement pathway. Activation of the alternate pathway also occurs; however, its expression is delayed and appears to be antibody-dependent.

Aspergillus fumigatus epidural abscess in a renal transplant recipient.

An epidural abscess caused by Aspergillus fumigatus occurred in a recipient of a cadaveric, renal allograft. The patient had persistent back pain and a peripheral neuropathy that involved the lower extremities. Signs of spinal cord compression evolved. No definite portal of entry was found. Diagnosis was made by histologic examination and culture of a biopsy specimen. Therapy, consisting of aggressive surgical debridement, intravenous amphotericin B, and oral flucytosine was unsuccessful in eradicating the organism. At postmortem examination, Aspergillus was identified at the abscess site. To our knowledge, aspergillosis presenting as an epidural abscess in the immunosuppressed, renal transplant recipient has not previously been reported and should be considered in the differential diagnosis of back pain and peripheral neuropathy in such a patient.

Lack of correlation between killing of gonococci by serum and antibodies directed against pili from strain 2686 of Neisseria gonorrhoeae.

In patients experiencing initial or repeated gonococcal infections there appeared to be little correlation between elevated levels of serum antibody to pili from Neisseria gonorrhoeae strain 2686 and the presence or absence of serum bactericidal activity against the patients' infecting isolates. Of eight patients who experienced their first gonococcal infection, four had elevated antipili antibody levels; all eight sera from patients who had repeated gonococcal infections had high antipili antibody levels. All the patients' sera were bactericidal for strain 2686 of N. gonorrhoeae.

Parameters of normal polymorphonuclear cell function in patients with repeated gonococcal infections.

The response to phagocytic stimuli was tested for polymorphonuclear (PMN) cells from gonorrhea repeaters, first-time infected patients, and never-infected controls. PMN function was assessed by measuring quantitative leukocyte iodination, glucose-1-C oxidation, and phagocytosis and killing of Staphylococcus aureus 502A. No significant differences in PMN function were noted for the three groups studied. However, white patients had significantly greater leukocyte iodination than black patients (p less than 0.05) and males tended to have greater leukocyte iodination than females (p less than 0.02). It is concluded that PMN cells from gonorrhea repeaters, first-time infected patients, and never-infected controls respond equally well to in vitro phagocytic stimuli. This implies that a significant defect in PMN cell function should not be implicated as a reason for the apparent susceptibility of gonorrhea repeaters to multiple genital gonococcal infections.