Detection of two Blastomyces dermatitidis serotypes by exoantigen analysis

Abstract

We evaluated the diagnostic value of antibody to Blastomyces dermatitidis A precipitin arcs for identifying B. dermatitidis cultures by the exoantigen technique with 88 isolates from the United States and Canada, 12 from Africa, and 1 each from India and Israel. In addition, we studied 190 mycelial-form isolates of other fungi which could be confused antigenically or morphologically with B. dermatitidis. Antigen extracts from all of the North American isolates, the Indian and Israeli isolates, and one of the African isolates reacted with the B. dermatitidis A antibody. The anti-A serum did not react with antigens from the other 11 African isolates or with antigens from any of the 190 heterologous fungi. Studies with unadsorbed and adsorbed antisera to selected North American and African isolates of B. dermatitidis showed that the North American isolates not only produced the distinct A antigen, but also formed another antigen that was common to all 11 of the antigenically less complex African isolates. The results of this study indicate that at least two serotypes of B. dermatitidis exist. All of the North American, Indian, and Israeli isolates and one of the African isolates contained the A antigen and were designated serotype 1. Most of the African isolates (11 of 12) constituted a second serotype that was deficient in A but showed an antigen designated K.

Serological differences in three Blastomyces dermatitidis strains - Serologische Unterschiede bei drei Blastomyces dermatitidis-Stammen

“…When probing with blastomycosis dog serum in a Western blot, both the T-58 and ERC-2 lysates displayed a major band in the molecular weight range previously described for Antigen A and WI-1 [10][11][12]. The Zaire lysates had no observable bands in this range (Fig.…”

“…Previous studies had shown that most African B. dermatitidis isolates did not have the major antigen found in North American B. dermatitidis, Antigen A. These have been designated serotype 2 [10][11][12]. Both the rabbit and dog sera assays indicated that the 48089 lysate did not have the same antigenicity as the other lysates, and this implied that this lysate might be serotype 2.…”

“…Another hypothesis would be that the human immune system recognized a different B. dermatitidis antigen from that recognized in the immune system of dogs. The antigen the humans recognized could be the K antigen that was noted, but never published, by Kaufman et al in 1983, which apparently was shared between the North American and African B. dermatitidis isolates [10,11]. To be able to discern the true reason for this result, it would desirable to conduct further studies using previously serotyped African isolates, a Colorado isolate, and other human serum specimens.…”

“…These African isolates were designated serotype 2. However, there is unpublished data which states that the two serotypes share a common antigen, Antigen K [10][11][12].…”

In Vitro Conversion of African Isolates of Blastomyces dermatitidis to Their Yeast For/In vitro‐Konversion afrikanischer Blastomyces dermatitidis‐Isolate zur Hefephase

“…A previous study (2) found that African isolates of Blastomyces dermatitidis required repeated subculturing onto fresh cottonseed agar to convert them from their mycelial to yeast form at 37 "C. At least three successive subcultures onto fresh medium every 10 days were required before complete conversion was obtained. Because of the success reported by Kane (1) with a partially defined medium, namely, Tween-albumin-niacin agar supplemented with casamino acids (KT), in converting mycelial North American isolates of B. dermatitidis to yeast form at 37 "C within 72 h, we decided to evaluate the KT medium.…”