Optimal antibody-receptor ratio in anaphylactic-sensitization.

The antigen-induced release of histamine from guinea pig and monkey lung fragments sensitized in vitro with hyperimmune rabbit antibody and human reaginic serum, respectively, was studied. When the amounts of whole antiserum, gamma-globulin fraction, or purified antibody were increased over the optimum in passive anaphylactic sensitization, the subsequent histamine release was reduced in spite of the fact that proportionately greater amounts of antigen were added to the system. The observed inhibition by higher antibody concentrations might be due to a reduction in cell-stimulating capacity of the antigen-antibody-receptor complex caused by inappropriate ratios among any of these three components.

Detoxified hymenoptera venoms: preliminary studies of in vitro cytotoxicity and antigenicity of Apis mellifera 'venomoid'.

The preparation of detoxified venom (venomoid) of Apis mellifera is described. The venomoid obtained by formaldehyde detoxification retained significant antigenicity. Radioallergosorbent test (RAST) inhibition studies indicated a loss of the affinity of the venomoid for the venom-specific human IgE antibody. In rabbits the venomoid was capable of producing precipitating antibodies which cross-reacted with the original venom. Cytotoxic activity of venomoid as measured by nonimmunological histamine release and hemolytic activity with human cells was not detectable in vitro. Further studies seem warranted for the establishment of a venomoid as a diagnostic and/or therapeutic agent in the management of the hypersensitivity reactions to venom.

Studies of the antigenicity and allergenicity of phospholipase A2 of bee venom.

The antigenic and allergenic properties of phospholipase A2 (PLA2) and whole bee venom were compared by measuring the IgG and IgE antibody responses in animals and man. Precipitating antibodies raised in rabbits and reaginic and other antibodies raised in mice reacted about equally with both bee venom and PLA. The majority of human sera containing bee venom-specific IgE also contained PLA-specific IgE, although in somewhat lower titers. Similarly, most human sera with significant amounts of total antibodies reacting with bee venom also had antibodies reacting with PLA. Histamine and SRS-a release from leukocytes of sensitive patients followed challenge with whole bee venom and PLA in the majority of instances. However, mediator release from several patients' cells was obtained with bee venom only. These studies suggest that although PLA is a major allergen and antigen in bee venom, significant exceptions in patients' reactivity may limit its potential diagnostic and therapeutic usefulness.

Inhibition of antigen-induced histamine release by ouabain.

The effect of ouabain, a specific sodium-potassium dependent adenosine triphosphatase (Na+-K+-ATPase) inhibitor, on antigen-induced histamine release was studied using guinea pig lung fragments sensitized in vitro with rabbit antibodies against bovine serum albumin. Histamine was assayed spectrofluorometrically. When sensitized tissue had been preincubated with ouabain (less than or equal to 1.0 x 10(-4) M) for 10 min prior to antigenic challenge, release of histamine was significantly inhibited (maximum 54%, p less than 0.001, N=9, paired t test). The most significant inhibition was obtained near the optimal concentration of antigen. The inhibition was dependent on the length of preincubation (less than or equal to 20 min), and was partially reversible upon washing the tissue removing the ouabain. Ouabain did not seem to prolong the duration of the histamine release process. Increase in potassium ion (less than or equal to 1.1 x 10(-2)M) inhibited the histamine release and had additive effects to ouabain action. Dibutyryl cyclic AMP (less than or equal to 5 x 10(-3) M), which could enhance the release, strongly antagonized the inhibition. Glucose removal from the medium did not abolish the ouabain effect. The results seem to indicate that immunologic release of histamine is under the influence of the membrane Na+-K+-ATPase activity.

Long-term study of the risk factors in atherosclerosis.

A study of the risk factors in atherosclerosis carried out in 595 subjects over a period of 10 years showed an increased prevalence of arterial hypertension, of high serum cholesterol values and of overweight in 1970 as compared to 1960. This rise was significant for all the parameters studied and was particularly evident in serum cholesterol values and overweight, beginning with the 21 to 30 age decade. The frequency of subjects with risk factors increased with age. During the period of study there occurred certain changes within the population such as an increase in the total consumption of calories and in the lipid contents of the food, as well as of the cultural level of the population. The authors show that the increase in the number of subjects with risk factors and the natural history of the various diseases or disturbances depend on the changes of living conditions and of environment.

The effect of Tris-buffered media and Tyrode physiologic saline solution on the antigenic release of histamine from human leukocytes.

Allergic histamine release from leukocytes was compared in three different media: Tyrode physiologic saline solution, Tris-buffered saline containing human albumin, calcium, and magnesium (Tris-ACM), and Tris-ACM with homologous serum. In a selected group of low histamine releasers, the maximal amount of antigenic histamine release was significantly higher in Tyrode solution as compared to Tris-ACM buffer. When homologous serum was added to Tris-acm, an enhancement of histamine release greater than with Tyrode solution was obtained. These results suggest that Tris-ACM may not be the optimal buffer for leukocyte histamine release experiments. Since Tyrode solution contains no serum proteins that bind slow-reacting substance of anaphylaxis or prostaglandins, the use of this medium may be advantageous for the study of the release of the chemical mediators from human leukocytes.