Reduction In Antibody Levels Research Articles

Immunotoxicity studies of PCB (Aroclor 1254) in the adult rhesus ( Macaca Mulatta) monkey — preliminary report

The effects of PCB (Aroclor 1254) on the immune system of adult female rhesus monkeys were investigated in a chronic study wherein five groups of monkeys (16/group) were administered (orally) PCB at levels of 0.0, 5.0, 20.0, 40.0 or 80.0 μg/kg body wt daily. Tests for immunotoxicity were initiated at 23 months of exposure to PCB, at which time the monkeys had achieved an apparent pharmacokinetic steady state based on the PCB concentration in fat and/or blood. A statistically significant ( P<0.05) dose response reduction in antibody levels (IgG and IgM) to sheep red blood cells (SRBC) was observed following i.v. administration of three immunizing doses of SRBC at weekly intervals. A statistically significant decrease in the percent T H and an increase in the percent and absolute T S lymphocyte levels was found in the 80 μg/kg body wt group compared to the control. The T H/ T S ratio was also significantly lower in the 80 μg/kg body wt group compared to the control. Other parameters investigated including percent of B-lymphocytes and total T-lymphocytes, total serum immunoglobulin levels (IgG, IgM and IgA), other serum proteins, glucocorticosteroid levels and lymphocyte transformation results following stimulation with the mitogens PHA-P and Con A were not affected significantly by PCB treatment. Additional immunologic parameters are currently being investigated to further elucidate the mechanism by which PCB induces immunotoxicity.

Psychological Factors Capable of Preventing the Inhibition of Antibody Responses in Separated Infant Monkeys

The capacity of infant squirrel monkeys to mount an antibody response to viral challenge was evaluated after removal from their mothers in several social and physical environments. Control and separated infants were injected with a benign virus, the bacteriophage X174, and levels of neutralizing antibody were assessed for 3 weeks. Infants separated alone in an unfamiliar environment showed a significant reduction in antibody levels as compared to control infants. Allowing infants to remain in the home environment, either alone or with peers, prevented this inhibition of antibody responses from occurring. Similarly, providing familiar peers in the novel environment facilitated the normal expression of antibody responses. These results indicate that the trauma of maternal separation is significantly reduced when infants are familiar with the separation environment or familiar social companions are available. The reduced antibody response was associated with the highest level of adrenal activation induced by the unfamiliar separation condition, but antibody titers and plasma cortisol levels could not be specifically correlated in individual infants.

Changes in intestinal fluid and mucosal immune responses to cholera toxin in Giardia muris infection and binding of cholera toxin to Giardia muris trophozoites.

The effect of Giardia muris infection on the diarrheal response and gut mucosal antibody response to cholera toxin was examined in mice. The results obtained showed that the fluid accumulation in intestinal loops exposed to cholera toxin was increased in mice infected with a low number (5 X 10(4) ) of G. muris cysts compared with the response in noninfected mice. This effect was associated with a marked reduction in absorption of oral rehydration fluid from the intestine. In contrast, mice infected with a high dose (2 X 10(5) ) of cysts showed a marked decrease in fluid accumulation in response to the toxin. This decrease might be related to the finding that both G. muris and Giardia lamblia trophozoites can bind significant amounts of cholera toxin. Evidence is presented which suggests that the gut mucosal antibody response, mainly immunoglobulin A but also immunoglobulin G, to an immunization course with perorally administered cholera toxin was depressed in mice infected with G. muris. The reduction in antibody levels was particularly evident when the primary immunization was made very early after infection. The serum antitoxin antibodies to the oral immunization with cholera toxin were, however, not affected. Likewise, the delayed-type hypersensitivity response against sheep erythrocytes in animals primed subcutaneously with sheep erythrocytes was not modified during the course of G. muris infection.

Humoral Immunity in Chicks Experiencing Marginal Vitamin B-6 Deficiency

An economical vitamin B-6-deficient ration that was palatable to broiler chickens was prepared and fed to 1-day-old chicks. The experimental ration was a typical soy-glucose ration. Vitamin B-6 was removed by washing the soybean meal with water. Microbiological analysis revealed that the washed ration contained 0.45 mg vitamin B-6 per kilogram. Experimental rations were formulated to contain 0.5, 1.0 and 3.0 mg supplemental pyridoxine · HCl per kilogram of ration. These supplemental levels produced the following total pyridoxine concentrations in the diet: 0.95, 1.48 and 3.18 mg pyridoxine · HCl activity per kilogram of diet. Chicks were grown to 7 weeks of age and characteristic vitamin B-6 deficiency signs were quantitated and/or observed. Notable signs in chicks receiving 0.5 mg added vitamin B-6 were increased mortality, decreased body weight gain and increased incidence of abnormal leg conformation. The humoral immune system of broiler chicks that were moderately deficient in vitamin B-6 was investigated. Marginal pyridoxine deficiency caused significant reduction in antibody levels to sheep red blood cells (SRBC) and relative levels of IgM and IgG during the peak and degradation phases of the primary response. During the hyperimmune response total anti-SRBC levels were not affected; however, relative levels of IgM and IgG were lowered.

Use of total lymphoid irradiation (TLI) in studies of the T cell-dependence of autoantibody production in rheumatoid arthritis.

The effect of total lymphoid irradiation (TLI) on T cell-dependent and -independent humoral immune responses was studied in patients with intractable rheumatoid arthritis (RA). The serum levels of several autoantibodies and of antibodies to diphtheria (DT) and tetanus (TT) toxoids and to pneumococcal polysaccharide (PPS; 12 antigenic types) were studied before and after TLI. In addition, the patients were given a booster injection of DT and TT and a single injection of pneumococcal vaccine after radiotherapy. Antibody levels to DT and TT decreased about twofold after TLI and did not rise significantly (p greater than 0.05) after a booster injection. However, there was no reduction in antibody levels to PPS after TLI, and a significant rise in titers was observed after a single vaccination (p less than 0.01). The serum levels of rheumatoid factor (RF), anti-nuclear antibody (ANA), and granulocyte associated IgG rose slightly after TLI. Thus, the autoantibodies and antibodies to polysaccharides appear to be relatively independent of helper T cell function, which is markedly reduced after TLI. On the other hand, antibodies to protein antigens such as DT and TT appear to be more closely dependent upon T helper function in man, as has been reported in rodents. The findings suggest that T cell-independent autoantibody responses alone do not maintain the joint disease activity in RA, because improvement in joint disease after TLI has been reported.

A modified rubella HI test using prestandardized reagents.

A modified haemagglutination inhibition test for rubella antibodies using prestandardized freeze-dried reagents was compared to a "standard" method. Tests of 707 serum samples showed that the modified test was sensitive and reliable by both macrotitration and microtitration techniques. The minor disadvantages of some reduction in antibody level when rubella sera were tested within one week of the rash and of spontaneous sheep erythrocyte agglutination in 0-7% of sera were out-weighed by the increased speed of the new test and the fact that it was carried out at room temperature.

Antitumor effects of antibody-diphtheria toxin conjugates. III. Cyclophosphamide-induced immune unresponsiveness to conjugates.

Of 9 hamsters immunized with diphtheria toxin-hamster gamma-globulin conjugates and rechallenged with this antigen 15 days later, 8 exhibited neutralizing antibodies against the conjugates 22 days after the initial immunization. Hamsters identically immunized, but also given cyclophosphamide (CY) 20 hours after the first immunization, had a much lower incidence of positive responses (2/10) and lower antibody levels in the positive responders. After further immunization with the conjugates, all CY-treated hamsters eventually developed neutralizing antibodies, but exhibited a reduction in antibody levels after a second exposure to CY. Hamsters immunized with diphtheria toxoid developed antibodies that were effective in neutralizing diphtheria toxin, but less effective against the diphtheria toxin conjugates.