William E. Greer

Psychological Stress, Early Response to Foreign Protein, and Blood Cortisol in Vervets

&NA; In this study, the focus of attention was the biological response of vervet monkeys (Cercopithecus aethiops) under psychological stress to a well‐defined protein, bovine serum albumin, with plasma cortisol as an indicator of alterations in the pituitary‐adrenocortical system. The term “psychological” was used simply to indicate that the stress aspects of the experimental situation were considered to have their impact upon the animals primarily by way of the sensory systems, rather than through direct physical or physiological trauma. After immunization, 5 animals were subjected to irregular noise, light, and vertical movement, while 5 controls remained undisturbed except for periodic blood collections. The stress group showed delayed antibody formation, and the antibodies rose to a lower level than in the control group. The serum cortisol values were markedly elevated during the initial period of the experiment in the group exposed to stress.

Low protein intake and response to Escherichia coli 055 infection in patas monkeys.

Patas monkeys (Erythrocebus patas) receiving a low protein diet were infected with a mildly enteropathogenicEscherichia coli 055 strain. The subsequent immunologic response including agglutinin, opsonin and immunocyte formation was reduced relative to controls which received full protein rations. The infective organisms were excreted for a longer time by patas given a low protein diet. Total serum protein and albumin declined in patas with a low protein intake. Immunoglobulin G, A and M measurements in the spleen, mesenteric lymph nodes and intestines after infection were less than those in the controls. Total RNA values and amino acid uptake decreased. A shift of the ribosomal fractions was observed. It was concluded that lack of dietary protein impaired protein synthesis, including that of cell-bound antibodies, and that it is feasible to use patas monkeys to study the relationship between enteric infections and protein malnutrition.

Response of Cercopithecus aethiops to cholera vibrio lipopolysaccharide and psychological stress

Abstract 5 African green monkeys were exposed to mental stress for 2 weeks, during which they were immunized with Watanabes lipopolysaccharide antigen prepared from an El Tor vibrio. 5 other animals were vaccinated with the same agent but were not exposed to stress. The El Tor haemolysin-inhibitory and the vibriocidal activities of the sera of the monkeys in both groups did not show significant differences, and the formation of agglutinins and coproantibodies, and the capability of the serum to neutralize the toxigenicity of the vibrios, in animals under stress, developed more slowly than in the control group. C. aethiops proved a feasible experimental animal for the study of antibody responses after the injection of a vibrio lipopolysaccharide.

Cholera studies in non-human primates: Part 8. Comparison of methods for the enumeration of immunologically active cells and early immune globulin, precipitin, vibriocidin and antitoxin formation☆

Abstract A chimpanzee was inoculated with 50 units of the choleragenic portion (Fraction 2) of Vibrio cholerae toxin. 24, 26 and 28 hours later samples of the spleen, liver, lymphatic nodes, the intestines, and blood were collected. The number of immunologically active cells was determined by the plaque procedure, the bentonite method, and the adhesion test. Precipitins, vibriocidal and toxin-neutralizing activity, as well as IgG, IgA, and IgM, were determined. DNA and RNA were also estimated. The bentonite and the adhesion tests proved to be valuable indicators of the immunological process. They demonstrated more IgG-producing cells than were found by the other procedures. The adhesion test was positive with a significantly smaller proportion of the cells manufacturing IgA and IgM than with IgG producers. It is possible that adhesion, as vibriocidal and antitoxic activity, is a function more closely related to immune globulins of smaller molecular weight. There was an increase in antibody-forming cells and in the enumerated antibodies as early as 24 to 28 hours after the antigen was injected, pointing towards the absence of a “negative phase” in immunization with this toxin. No significant changes of DNA and RNA could be found by microchemical methods at this early stage of the development of immunity.

Avidity of cholera antibody

Abstract IgA, IgA, and IgM of the serum and intestinal wall of chimpanzees, and of human serum, were studied after antigenic stimulation with cholera toxin. Antibody avidity at various pH values was determined. The cholera toxin neutralizing and the haemagglutinating capability of the native Ig-s as well as the Ig-s liberated from antibody-antigen complexes were investigated. The avidity of IgM and non-secretory IgA increased, whereas that of IgG and secretory (intestinal) IgA did no change essentially during 14 days following antigenic stimulation. Relatively large amounts of toxin were bound by IgG and secretory IgA. The haemagglutination titres increased but did not parallel antitoxin formation and Ig-antiboty avidity in the intestinal tissue. The need for antitoxin studies in persons exposed to cholera was emphasized.

Gallbladder damage and prolonged excretion of cholera vibrios in Erythrocebus patas.

Summary Mechanical damage and implantation of pumice stones into the gallbladder of patas monkeys seemed to extend the period of excretion of vibrios, principally in animals not vaccinated parenterally with the homologous strain. The administration of live El Tor vibrios, without surgery, also appeared to induce pathological changes in the gallbladders of some unvaccinated animals. The vibriocidal activity titers remained elevated for a longer time in animals that excreted vibrios for an extended period.