Tatsushi Ishizaki

Allergenic identity between the common floor mite (Dermatophagoides farinae Hughes, 1961) and house dust as a causative antigen in bronchial asthma

Abstract Since various kinds of mites are contained in house dust in significant numbers, the possibility of antigenic similarity between house dust and the mites in it was investigated. D. farinae , purely cultivated in our laboratory, was used in this study. Although it makes up only 4 per cent of the total mite population in house dust, very close correlation between house dust extract and mite extract was found in skin tests. Most of the antigenic substance stays inside of the Visking tube after dialysis, but a certain amount was dialyzed out. All cases with positive inhalation provocation tests with house dust extract reacted positively to the mite extract. Skin-sensitizing antibody was detected against the mite in sera from the patients allergic to house dust. Skin-sensitizing antibody was almost completely neutralized with house dust extract against the mite extract and vice versa, in vitro as well as in vivo. From these results, it was concluded that the mite is one of the major antigenic substances in house dust, and mites most likely have cross-antigenicity with each other.

Cross-antigenicity among six species of dust mites and house dust antigens

Abstract Body and excreta of Dermatophagoides farinae were found to be an important allergen in house dust. However, house dust contained more than 35 species of mites. The major mites in house dust are Glycyphaginae and D. pteronyssinus , which make up 31.8 per cent and 27.2 per cent, respectively. D. farinae comprises only 4 per cent of the total mites, as an average, in house dust in Japan. Consequently antigenic relationships between house dust and 6 species of mites, including D. farinae , were studied by the method of the skin testing and the in vitro neutralization of skin-sensitizing antibody. It was found that D. farinae was most closely related to house dust antigen in comparison with 5 other species of mites: Chortoglyphus arcuatus , Blomia sp., Aleuroglyphus ovatus, Suidasia nesbitti , and Tyrophagus putrescentiae . Cross-antigenicity was found among these mites although this was not complete, and it was considered that each species of mite had its own characteristic antigen. Moreover, the antigenicity of D. farinae was quite potent, and D. farinae appeared to possess the major common antigen among these species of mites. Consequently the existence of identical antigenicity between house dust and D. farinae was not surprising even though D. farinae constituted only a few per cent of the mites in house dust in number. D. farinae and C. arcuatus were more potent in skin reactivity in comparison with other species of mites, but cross-antigenicity between these 2 species of mites was not as close as that between the other species. The bodies of mites had identical antigenicity with the excreta.

Antigenic relation between house dust and a dust mite, Dermatophagoides farinae Hughes, 1961 , by a fractionation method

Abstract Both house dust and mite ( Dermatophagoides farinae Hughes, 1961) extracts were filtrated through Sephadex G-50 and 200 with I 131 -labeled human serum albumin and phenol as indicators. Protein and sugar contents of each constituent were determined by absorbance at 280 mμ and by a slightly modified anthrone method, respectively. The end point of skin test-eliciting capacity with twofold dilutions of each fraction was determined in 6 house dust-sensitive subjects. The tube numbers of the eluent of the house dust or the mite extract containing the most potent antigen eliciting skin reactions in house dust-sensitive subjects agreed with each other, but these fractions did not necessarily match the protein or sugar content. Moreover, these potent fractions did not appear to match the antigen producing precipiting bands against antiserum of the experimental animals. Consequently, it was thought that the most allergenic constituent in house dust and mites is not necessarily the most antigenic in experimental animals. Considering the location of the most potent, active eluate in allergic subjects on Sephadex, the molecular weight of such antigen was thought to be larger than 10,000 but smaller than 69,000, and the composition of such antigen was considered to be probably a protein and polysaccharide conjugate. Further study in this line is in progress.

Locomotion of Ascaris suilla et lumbricoides and the influence of anthelminthics upon them.

At the present time, ascariasis is to be considered as one of the serious medical problems in the oriental countries including Japan. In many human experiments in our country, it is found that both santonin and hexylresorcinol are reliable in their anthelminthic action (1). From the result of comparable studies on the pharmacological as well as clinical benefits of both drugs, it is confirmed that santonin is markedly superior to the other in view of its negligible side action. Effective doses of santonin never induce ill effects except a slight and temporary disturbance in vision, while oral administration of hexylresorcinol induced some local irritations on the mucous membrane of the digestive organ, even when it was administered under a perfect condition of coating on it. After taking santonin, ascaris are expelled alive and active. Some authorities, therefore, assume that santonin is not directly toxic to the parasites, but that rather they are irritated by the drug and migrate from the small intestine to the colon to be expelled (2-6). According to others, the drug is excreted in the intestine as an unknown compound, possibly an oxidation product, on which the ascaricidal properties may depend (7-12). But there has been no positive evidence to support both of the views until recently. We have now been able to find out a characteristic locomotion of ascaris in a glass tube which is made to imitate the shape of the bowel, and have good reasons to connect this movement of the worm closely with the anthelminthic activity of santonin (13).