Allergenicity of major component proteins of soybean

Allergenic activities of major component proteins of soybean 11S-, 7S- and 2S-globulins were examined by the radioallergosorbent test (RAST) and by RAST inhibition experiments with the sera from soybean-sensitive patients. The reactivity with specific IgE antibody was found in all fractions. There was considerable cross-reactivity among three fractions, and 2S-globulin had the highest allergen potency to inhibit the RAST against 11S, 7S- and 2S-globulin. When the fractions were heat-treated at 80, 100 and 120 degrees C for 30 min, the RAST reactivity of 2S-globulin heated at 80 degrees C for 30 min was slightly enhanced, while that of others was reduced to 39--75% of that of the native globulin. IgE antibody could be produced in BALB/c mice only with one of the three fractions, i. e. 2S-globulin, and the produced IgE antibody lacked reactivity with 11S- and 7S-globulin.

Allergenicity and lymphocyte-stimulating property of rice protein

Two protein fractions of rice, grain, glutelin and globulin, were prepared by dilute alkali and salt extraction, respectively. The globulin fraction was separated into G1-1, G1-2, and G1-3 fractions by Sephadex G-200 column chromatography. The allergenic activities and lymphocyte-stimulating properties of these fractions were investigated by the radioallergosorbent test (RAST) with sera from 6 individuals who showed immediate skin reaction to soluble rice extract and by 3H-thymidine incorporation tests with 5 subjects with indurated skin reaction of delayed onset. All fractions were found to be reactive with specific IgE antibody, and G1-1 and G-2 revealed lymphocyte-stimulating activity. RAST inhibition revealed considerable cross-reactivity of IgE antibody with the glutelin and globulin fractions. When the glutelin and globulin fractions were heated at 60 degrees C for 1 hr, 100 degrees C for 2 min, or 100 degrees C for 10 min, RAST activities were reduced to 40%-70% of native. On the other hand, lymphocyte-stimulating activities of the globulin fraction heated at 60 degrees C for 1 hr or 100 degrees C for 2 min were enhanced up to 6 times of native activities, while those of identically treated glutelin fractions remained unchanged.

Induction of lymphocyte colony formation in vitro by protein A

Human lymphocyte colonies were grown in semi-solid culture in the presence of staphylococcal protein A. The best results were obtained when 1 X 10(6) lymphocytes were cultured for 5 to 7 days with 25 to 50 microgram of protein A per dish. A lineal relationship was observed between the number of cells seeded and the number of colonies developed. An increased number of colonies was seen in cord blood culture compared with that in child and adult peripheral blood. The addition of 5 X 10(-5) M of 2-ME to the culture approximately doubled the colony counts. The cells harvested from the colonies contained about 70% of E-RFC and 20% of EAC-RFC.

Discrepancy between skin reactivity and blastogenic activity of fractionated PHA-P

Firstly, it was reported that phytohemagglutinin P (PHA-P) can induce the immediate skin reaction besides the delayed one. 70 out of 80 cases (87.5%) gave positive immediate reactions with 1 mug of PHA-P. There was a close correlation between the radioallergosorbent test (RAST) counts against PHA-P and the total IgE value or erythematous diameter of the immediate skin reactions. Absorption with anti-IgE or PHA-P reduced the RAST counts against PHA-P to 79 and 56% of their initial values, respectively, but did not effect the RAST counts against steptokinase-streptodornase (SK-SD). These results suggest that the immediate skin reaction might be induced by specific IgE antibody against PHA-P. Secondly, using three fractions of PHA-P obtained by Sephadex G-200 gel filtration, skin test and RAST in humans, ACA in rats, and 3H-thymidine incorporation into human leukocytes, were carried out and data obtained that showed some discrepancy between them. That is, on skin testing, it was shown that all of the three fractions (fr.) had the ability to elicit the immediate and delayed skin reaction in humans and rats with the order of fr. 1, 2 and 3, and it was confirmed by RAST. On the other hand, the leukocyte-stimulating activity resided in fr. 1 and 2, while fr. 3, which seemed to be a group of subunits with a molecular weight of around 35,000, had almost no activity. These findings have been discussed in view of the earlier studies on the structure of PHA-P

Inhibition of 3H-thymidine incorporation into human lymphocytes by dialyzable material of streptokinase- streptodornase

Using the 3H-thymidine incorporation test, the lymphocyte-stimulating activity of streptokinase-streptodornase (SK-SD, Varidase) and its fractions were evaluated. The dose-response curves of all the preparations except the third fraction had two peaks with the maximum around 5 and 40 mug. The dialyzable fraction of Sk-SD (D-SK-SD) occupying approximately half of the original sample had almost no lymphocyte-stimulating activity; and conversely, it had a potent inhibitory effect on the 3H-thymidine incorporation into lymphocytes that normally occurs with non-dialyzable SK-SD (ND-SK-SD), PPD and PHA-P. Therefore, it will be desirable to remove the dialyzable fraction from the commercial SK-SD preparation when it is used for the determination of the capacity of cellular immunity against tsk-sd.