Increased 'T lymphocyte' bearing Fc receptors for IgG in pregnancy.

T cell subpopulations as defined by E rosette formation and Fc receptors for immunoglobulins were determined, using ox red blood cells coated with the IgG or IgM fraction of rabbit anti-ox red blood cells antibody to form rosettes with the peripheral blood lymphocytes of 18 pregnant females and 12 healthy nonpregnant females. It was shown that the TG cell population in the pregnant females is significantly increased as compared to those in the nonpregnant controls (mean +/- SEM % TG cells: 18 +/- 1.2 vs. 9.6 +/- 0.7; p less than 0.001). By using peripheral blood from normal nonpregnant subjects it was also shown that TG cells suppressed one-way mixed lymphocyte reactions (mean +/- SEM suppression: 23 +/- 7.2; p less than 0.01). These findings suggest that the TG cell population may exert a suppressor function on the immune response to alloantigens and act in concert with other humoral factors to protect the fetus from rejection.

Allergens in yellow jacket venom as determined by sephadex fractionation, enzyme and RAST assays.

Yellow jacket venom (YJV) was fractionated on Sephadex G-50 and G-75 resulting in 9 fractions. These fractions were examined for enzyme and RAST activity using sera from 10 patients with known positive YJV RAST. Enzyme activity was found in four fractions. Enzymes associated with significant RAST activity were acid phosphatase, hyaluronidase, phospholipase A and phospholipase B. DNAase activity was found in one of the fractions associated with phospholipase A and B. Positive RAST activity was found in 8 of 9 fractions. The RAST patterns and relative RAST activities among the patients' sera examined were quite variable. The heterogeneity of the antibody response to the YJV fractions among the sera studied suggests that testing and treatment could not be successfully carried out in all patients using one or two predominant venom antigens.

Comparison of venom and whole-body rast and intradermal testing in vespid-sensitive patients.

14 patients clinically hypersensitive to vespid sting by history, 6 patients with large local reactions and 10 control subjects were skin tested with serial two- and tenfold dilutions of venom and whole-body extract of yellow jacket, wasp, and white-faced hornet antigens. Radioallergosorbent test determinations with the same antigens were also made. Determination of minimal reactive dose by skin testing distinguished control and hypersensitive patients groups for all three antigens using either venom or whole body extract. Yellow jacket venom skin testing detected 12 of 14 patients considered clinically hypersensitive. This was not the case with the other two venoms, possibly because most of the patients were yellow jacket sensitive, or any of the whole-body extracts. The Radioallergosorbent test was less useful than venom skin testing in detecting patients considered clinically sensitive.

Correlation of serum theophylline levels with inhibition of allergen and histamine-induced skin tests.

The purpose of this study was to determine if clinically effective serum levels of theophylline have an inhibitory effect on intradermal tests for allergic hypersensitivity. Intradermal testing using the threshold-dilution technique was performed in 9 patients, 7 of whom were sensitive to 2 antigens. Testing was performed over a 6-hour period after theophylline administration and compared with the control results. Inhibition of the end-point was demonstrated with 12 of 16 antigens tested associated with serum theophylline levels ranging from 7 to 20 microgram/ml. Marked inhibition of the intradermal tests, that might have clinical significance, only occurred with 4 antigens.

Clinical comparison of skin testing and the radioallergosorbent test in dog-sensitive patients using mixed and breed-specific antigens.

A study of clinical history, intradermal test end points and RAST values with six different dog antigens was made in 20 patients and 5 control subjects. Skin testing was found to be more useful clinically than the RAST. Considerable variability among mixed epidermal extracts was noted. There was no apparent advantage to testing with three individual-breed extracts studied, compared to the most potent mixed epidermal antigen. The results of this study suggest that further efforts toward standardization of potency, methods of preparation and, possibly, breed composition of dog allergenic extracts are required to develop improved allergens for clinical use.

Modulation of human T lymphocyte rosette formation by autonomic agonists and cyclic nucleotides.

Early rosette formation by T lymphocytes appears to be modulated by cyclic nucleotides. Dibutyryl cyclic 3',5' adenosine monophosphate (cyclic AMP) 10(-2) M inhibited E rosette formation up to 83%, while 10(-6) M 8-bromo-cyclic guanosine monophosphate (cyclic GMP) increased rosette formation maximally to 67.4% with less pronounced effect at increased concentrations. T lymphocyte receptors for beta adrenergic, alpha adrenergic, and muscarinic cholinergic agonists appear to influence rosette formation. Isoproternol 10(-2) M induced 67.3% inhibition, while phenylephrine 10(-5) M and carbamylcholine 10(-4) M were associated with enhanced rosette formation of 67.2% and 57.8%, respectively. Selective blockade with propranolol, phentolamine, and atropine indicated the presence of separate receptor sites. The lack of effect of histamine at concentrations of 10(-3) M and above suggests the absence of specific recepotrs on peripheral human T lymphocytes.

Fetuin. In vitro effect on sheep erythrocyte rosette formation with human T lymphocytes.

Peripheral blood lymphocytes from six healthy control subjects were incubated in vitro with fetuin and enumerated for sheep erythrocyte rosette forming T cells. Significant enhancement of rosette-forming T lymphocytes was observed in a dose-related manner. The physical presence of fetuin is not required for this effect. Incubation of lymphocytes with human AB serum has no significant effect on the rosette formation. This enhancing effect of fetuin appears to be secondary to alteration in T lymphocyte surface receptors for sheep erythrocytes.