Pathogen Antibody Research Articles

Diagnosis of respiratory virus infections using GACELISA of urinary antibodies

Sensitive and specific methods are needed to diagnose respiratory virus infections using body fluids such as urine that, unlike blood samples, are readily obtained by non-invasive means. Immunoglobulin G antibody capture enzyme-linked immunosorbent assays were developed for detection of antibody rises to respiratory syncytial virus and influenza A/Taiwan 3H1N1) after initial quantification and adjustment of urinary IgG concentration. Of 24 elderly subjects whose sera were assayed by the complement fixation test for antibody to RSV, seven had convalescent titres ≥ 32, and five had ≥ 4-fold rises in titre. Acute and convalescent urines for six of these seven subjects were tested for virus-specific urinary IgG by GACELISA. Four of four persons with ≥ 4-fold rises in CFT had urine ELISA convalescent to acute ratios of ≥ 1.8 whereas two subjects with convalescent CF titres > 16, but no increase in serum antibody titre, had urine convalescent/acute ratios of 1.0. Ten subjects with ≥ 4-fold rises in CFT or HI antibodies to influenza A/Taiwan had urine ELISA ratios of ≥ 1.4 when samples taken on the day of influenza vaccination and 16 days later were compared. These preliminary observations demonstrate clinically significant rises in respiratory pathogen antibody levels between acute and convalescent urine samples, provided that total urinary IgG concentrations are quantified and then standardised.

Relationship of Common Avian Pathogen Antibody Titers in So-Called Chicken Anemia Agent (CAA)-Antibody-Positive Chicks to Titers in CAA-Antibody-Negative Chicks

Antibody titers for infectious bursal disease virus (IBDV), infectious bronchitis virus, Newcastle disease virus, and reovirus from chicks with chicken anemia agent (CAA) antibodies were compared with antibody titers from their CAA-antibody-negative counterparts. These comparisons were made in 396 chickens that were 1 day, 2 weeks, 8-9 weeks, 10 weeks, 17 weeks, or 29-32 weeks old. Only one serum sample was collected from any given chick or chicken. There were no significant differences between the antibody titers at any age for any antigen, with one exception: at 29-32 weeks, the IBDV titers were higher (t = 2.62, df = 142, P less than 0.01) in chickens with CAA antibody. Although not at all likely, we believe that the observation of high IBDV antibody titers in CAA-antibody-positive chicks could have been a spurious one.

Monoclonal and polyclonal antibodies both block and enhance transmission of human Plasmodium vivax malaria.

Antibodies against gametes of the malarial parasite inhibit the development of the parasite in the mosquito and curtail the transmission of malaria. We now report that a monoclonal antibody against gametes of the human malaria pathogen Plasmodium vivax and antibodies induced during natural infections of P. vivax in humans which suppress infectivity of the parasites to the vector at high concentrations can, at lower concentrations, have the opposite effect and enhance the level of malaria infection in the mosquitoes. Infectivity enhancing effects of up to 12-fold were demonstrated when a transmission blocking monoclonal antibody and immune human sera were diluted, in some undiluted immune human sera, and in the sera of vivax malaria patients during convalescence after drug cure.

Measurement of serum and salivary antibodies to the oral pathogen Bacteroides asaccharolyticus in human subjects

Antibodies against a capsular antigen of Bact. asaccharolyticus were measured in the serum (IgG) and saliva (IgA) by an enzyme-linked immuno-sorbent assay, ELISA. Serum IgG levels, measurable at all ages in a group of 143 subjects, increased with advancing age. Similar levels of IgG were present in a group of 8 patients with adult, rapidly advancing periodontitis and in 3 patients with juvenile periodontitis (periodontosis). Antibody levels in periodontitis were not significantly different from those of age-matched normal subjects. Levels of salivary IgA against Bact. asaccharolyticus determined in healthy volunteers and in adult and juvenile periodontitis patients were not statistically different among the three groups. Despite the putative importance of Bact. asaccharolyticus as a periodontal pathogen, serum IgG and salivary IgA antibodies against a capsular antigen from this organism appear to exist in similar quantities in controls and periodontitis patients.