Alkaline proteases were produced by a virulent strain of Aspergillus fumigatus during growth on media containing glucose and proteins or peptides. After isoelectric focusing, six bands of proteolytic activity were detected with synthetic substrates after blotting on nitrocellulose membranes. The main protease (pI = 8.6) corresponded to the known subtilisin-like protease Alp of A. fumigatus and five minor components had lower isoelectric points (8.1 to 5.2). All proteases were produced on different media and in various phases of growth with only small quantitative variations. They also had identical pH optima, were denatured above 45 degrees C and stabilized by Ca2+ ions, were affected by the inhibitors of serine proteases only and had nearly identical substrate specificity against 13 synthetic substrates. On gel chromatography the three most acidic components had higher molecular weights than the main enzyme Alp. It remains to be determined if the enzymes under study arise through posttranslational processing of the main protease or are true isoenzymes, products of a gene family.

The heat shock response, characterized by increased expression of heat shock proteins (Hsps) is induced by exposure of cells and tissues to extreme conditions that cause acute or chronic stress. Hsps function as molecular chaperones in regulating cellular homeostasis and promoting survival. If the stress is too severe, a signal that leads to programmed cell death, apoptosis, is activated, thereby providing a finely tuned balance between survival and death. In addition to extracellular stimuli, several nonstressfull conditions induce Hsps during normal cellular growth and development. The enhanced heat shock gene expression in response to various stimuli is regulated by heat shock transcription factors.

Protein pattern changes were investigated in the filamentous fungus Trichophyton mentagrophytes during the morphological transition induced by increased temperature and higher CO2 partial pressure in cultivation atmosphere. The differences between the mycelial and the arthroconidial phase were characterized by SDS-PAGE and by immunodetection with mouse polyclonal antibodies. The components found by Western blotting in mycelia were 88, 86, 32, 29, 19.5, 18.5 kDa, in arthroconidia 108, 92, 88, 66, 56, 41, 39, 19.5 kDa. The results suggest the participation of some heat shock associated proteins of T. mentagrophytes in host immune response against mycotic infection.

Three sequences of hsp60 from Saccharomyces cerevisiae, Schizosaccharomyces pombe and Histoplasma capsulatum were compared. Local multiple alignment of these sequences allowed the selection of two oligonucleotides suitable as primers for the polymerase chain reaction. This primer set was used for the amplification of a part of the hsp60 gene from cDNA of Trichophyton mentagrophytes and S. cerevisiae. Similar fragments detected in both PCR's imply the possible future use of the developed primer set for the detection of the hsp60 gene in other fungal species.

The review concerns heat shock proteins and their significance in immune reactions. It focuses on problems of physiological and pathological interactions in etiology and duration of autoimmune diseases and infection processes, especially fungal infections. New trends are described in exploitation of heat shock proteins for preparation of specific protective vaccines.