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Human herpesvirus complement regulatory proteins
HUMAN HERPESVIRUS COMPLEMENT PROTEINS
REGULATORY
Nell R. Cooper and Bonnie M Bradt The Scripps Research Institute, La Jolla, CA Viruses and other microorganisms efficiently activate the complement system, in the presence or absence of specific Ab. Despite such efficient recognition by C and adaptive immune responses, viruses and other pathogens have not only survived but thrived, due to their ability to successfully elude recognition and destruction by host defense mechanisms. Pathogens have evolved a number of distinct mechanisms to accomplish these goals. Particulady interesting is the mimicry of mammalian C regulatory functions by microorganisms. We have found that three human herpesviruses possess the ability to regulate activation of the human C system. Each exhibits a unique spectrum of C regulatory activities. In recent studies, purified herpes simplex virus type-I (HSV-1), an alphaherpesvirus, was found to possess factor I dependent cofactor activity for C3b cleavage but to lack the ability to accelerate decay of the ACP C3 convertase. HSV-1 thus possesses two distinct C regulatory activities, since earlier studies by others showed that isolated HSV-1 glycoprotein C (gC-1) possesses decay accelerating but not cofactor activity. Our recent work also indicates that purified human cytomegalovirus, a betaherpesvirus, possesses potent factor I cofactor activity and ACP C3 convertase decay accelerating activity and binds C3b. Our earlier studies (Mold, C. et. al., J. Exp. Med. 168:949, 1988), recently reinvestigated, showed that Epstein Barr virus, a gammaherpesvirus, also possesses cofactor and decay accelerating activities but does not bind C3b. The relative potency of these activities in the three viruses differs markedly on a per virion basis. The spectrum of activities differs from that of the known C regulatory proteins, rendering it unlikely that the viruses have acquired human C regulatory activities from the cells in which they are produced. These C regulatory properties would be anticipated to provide these viruses with a survival advantage.
INCREASED EXPRESSION OF Clq RECEPTOR ( C O L L E C T I N R E C E P T O R ) ON N E U T R O P H I L S FROM INFLAMMATORY JOINT FLUIDS A D Crockard, R. Malhotra~., J. M Thompson., T. A. McNeill and R. B. Sim ~. Regional Immunology Laboratory, Royal Victoria Hospital, Queen's University of Belfast, Belfast, Northern Ireland, UK. aMRC Immunochemislry Unit, Department of Biochemistry, University of Oxford, Oxford, OXl 3QU, UK C l q receptor (ClqR) expression was determined by immunofluoresence flow cytometry on neutrophils from paired peripheral blood and synovial fluid samples from 21 patients with rheumatoid arthritis (RA) and 13 patients with other articular diseases (OAD). In both patient groups the levels of ClqR on circulating neutrophils were similar to those observed for normal control subjects, whereas on synovial fluid neutrophils significantly higher levels of receptor expression were observed. The mean percenlage increases in receptor expression in synovial fluid neutrophils compared to circulating neutrophils were: RA patients 47%; OAD patients 72%. Clq bearing immune complexes were most prevalent in patients with RA, with the highest concentration being found in synovial fluid samples. No correlation between immune complex levels and neutrophil ClqR expression was noted. Upregulation of ClqR expression is a feature of activated neutrophils from inflammatory joint fluids.
A N T I ~ Y ACTIVITY OF F1 D I W F F ~ T STRAINS OF P a r a c o c c i d i o i d e s
FRACTIONS ISOTAT~ brasiliensis.
FROM
Crott, L.S.P. I, Michelin, M.A. 2, Teixeira, J.E. 2, Silva, C.L. 2 & Barbosa, J.E. 2'3 iDep. An~lises Cl[nica, Faculdade de Ciencias
Farmac~uticas
Ribeirao
Microbiologia
Preto,
Imunologia,
USP,
2Dep.
Parasitologia,
Faculdade de Medicina de
Ribeir~o
Preto,
3Lab. de Imunologia Cl[nica, Hospital das Cl[nicas da
USP
de e and
Faculdade
de Medicina de Ribeirao Preto, USP - Brazil. It has been previously demonstrated that there are variations in the development and modulation of lesions induced by different strains of Paracoccidioides brasiliensis, as well as several clinical forms of the disease which are dependent on host factors as well as factors related to the fungus. The alkali-insoluble cell wall polysaccharide fraction (FI) from this fungus has been considered to be important factor in the pathogenesis of the granulomatous lesions observed in this mycosis~ and the capacity of FI to activate the complement system may explain, at least in part, this phenomenon. The aim of our study was to investigate differences that might exist in the activation of human complement system by FI fractions from four different strains of P. brasiliensis. Strains HC and 18 (virulent)~ 265 (avirulent)~ and 9 (intermediate virulence) were used; before the experiments~ the virulence of strains HC and 18 was recovered by in vivo passage in guinea pigs. The four strains of the fungus were processed for purification of the F1 fractions and the activation of human complement system was studied by a kinetic method of hemolytic activity measurement. The incubation of F1 fractions in normal human serum resulted in different degress of inhibition of the hemolytic activity of the alternative pathway (d50 observed were: 193.24 ug (HC); 147.03 ug (18); 113.98 ug (265), and 108.12 ug (9) and classical pathway (d50 observed were: 107.66 ug (HC): 61.76 ug (265); 83.95 ug (18), and 63.14 (9). The FI fraction from the avirulent strain was more efficient in activating both pathways of human complement than the F1 fraction from the virulent strains (HC and 18). These differences in the behavior of the F1 fractions in relation to human complement activation may correlate with the virulence of strains and may contribute to the understanding of the variations observed in the infection induced by different fungal strains.
C4 A N D
BF POLYMORPHISMS
POPULATION AND A GROUP TUSCANY (ITALY).
IN A T U R K I S H
OF ETRURIANS
OF
M. Cuccia 1, A. Brega 2, B. Kirdar 3, A. Cortellazzo, 1 G. Peloso4. 1 Dip. Genetica e Microbiologia, Univ. di Pavia, (Italy) 2 Dip. Biologia e Genetica per le Scienze Mediche, Univ. di Milano (Italy), 3 Dept. of Biology, Bogazici University, Istanbul, (Turkey), 4 Ist. di Medicina Legale, Univ. di Pavia, (Italy) Human HLA complement C4 and BF genes are located on the short arm of chromosome six and their products show extensive genetic polymorphism. The C4A, C4B and BF polymorphisms have been studied in a group of 203 unrelated individuals (111 from Volterra, Tuscany, Italy and 92 taken in Istanbul, Turkey) both at protein and partially at DNA level. The frequency of BFF allele in Turkish population is 26.40%: the two subtypes FB and FA was obtained by isoelectric focusing method and are present respectively in 8.3% and 17.05%. The rare SO allele was present in two individuals of Istanbul (1,2%); the F1 variant was not present as the allele C4A4. The null alleles have frequencies respectively C4AQO 12.94% and C4BQ0 5,29%. Two C4A duplication have been found. BFSO.7 allele reaches a frequency of 3.15% in Tuscany, where the BFS (71.17%) seems low compared with other Northern population of Italy (77.09%). The Turkish group of individuals have been studied also for other polymorphisms of RBC and serum protein: Gliossalase I (GLO I), Phosphoglucomutase 1 (PGM1), Esterase D (EsD), Aptoglobins (HP), Group Specific Component (Gc). Genetic distances among these and other Italian and Albanian populations are calculated.
REGULATORY
Nell R. Cooper and Bonnie M Bradt The Scripps Research Institute, La Jolla, CA Viruses and other microorganisms efficiently activate the complement system, in the presence or absence of specific Ab. Despite such efficient recognition by C and adaptive immune responses, viruses and other pathogens have not only survived but thrived, due to their ability to successfully elude recognition and destruction by host defense mechanisms. Pathogens have evolved a number of distinct mechanisms to accomplish these goals. Particulady interesting is the mimicry of mammalian C regulatory functions by microorganisms. We have found that three human herpesviruses possess the ability to regulate activation of the human C system. Each exhibits a unique spectrum of C regulatory activities. In recent studies, purified herpes simplex virus type-I (HSV-1), an alphaherpesvirus, was found to possess factor I dependent cofactor activity for C3b cleavage but to lack the ability to accelerate decay of the ACP C3 convertase. HSV-1 thus possesses two distinct C regulatory activities, since earlier studies by others showed that isolated HSV-1 glycoprotein C (gC-1) possesses decay accelerating but not cofactor activity. Our recent work also indicates that purified human cytomegalovirus, a betaherpesvirus, possesses potent factor I cofactor activity and ACP C3 convertase decay accelerating activity and binds C3b. Our earlier studies (Mold, C. et. al., J. Exp. Med. 168:949, 1988), recently reinvestigated, showed that Epstein Barr virus, a gammaherpesvirus, also possesses cofactor and decay accelerating activities but does not bind C3b. The relative potency of these activities in the three viruses differs markedly on a per virion basis. The spectrum of activities differs from that of the known C regulatory proteins, rendering it unlikely that the viruses have acquired human C regulatory activities from the cells in which they are produced. These C regulatory properties would be anticipated to provide these viruses with a survival advantage.
INCREASED EXPRESSION OF Clq RECEPTOR ( C O L L E C T I N R E C E P T O R ) ON N E U T R O P H I L S FROM INFLAMMATORY JOINT FLUIDS A D Crockard, R. Malhotra~., J. M Thompson., T. A. McNeill and R. B. Sim ~. Regional Immunology Laboratory, Royal Victoria Hospital, Queen's University of Belfast, Belfast, Northern Ireland, UK. aMRC Immunochemislry Unit, Department of Biochemistry, University of Oxford, Oxford, OXl 3QU, UK C l q receptor (ClqR) expression was determined by immunofluoresence flow cytometry on neutrophils from paired peripheral blood and synovial fluid samples from 21 patients with rheumatoid arthritis (RA) and 13 patients with other articular diseases (OAD). In both patient groups the levels of ClqR on circulating neutrophils were similar to those observed for normal control subjects, whereas on synovial fluid neutrophils significantly higher levels of receptor expression were observed. The mean percenlage increases in receptor expression in synovial fluid neutrophils compared to circulating neutrophils were: RA patients 47%; OAD patients 72%. Clq bearing immune complexes were most prevalent in patients with RA, with the highest concentration being found in synovial fluid samples. No correlation between immune complex levels and neutrophil ClqR expression was noted. Upregulation of ClqR expression is a feature of activated neutrophils from inflammatory joint fluids.
A N T I ~ Y ACTIVITY OF F1 D I W F F ~ T STRAINS OF P a r a c o c c i d i o i d e s
FRACTIONS ISOTAT~ brasiliensis.
FROM
Crott, L.S.P. I, Michelin, M.A. 2, Teixeira, J.E. 2, Silva, C.L. 2 & Barbosa, J.E. 2'3 iDep. An~lises Cl[nica, Faculdade de Ciencias
Farmac~uticas
Ribeirao
Microbiologia
Preto,
Imunologia,
USP,
2Dep.
Parasitologia,
Faculdade de Medicina de
Ribeir~o
Preto,
3Lab. de Imunologia Cl[nica, Hospital das Cl[nicas da
USP
de e and
Faculdade
de Medicina de Ribeirao Preto, USP - Brazil. It has been previously demonstrated that there are variations in the development and modulation of lesions induced by different strains of Paracoccidioides brasiliensis, as well as several clinical forms of the disease which are dependent on host factors as well as factors related to the fungus. The alkali-insoluble cell wall polysaccharide fraction (FI) from this fungus has been considered to be important factor in the pathogenesis of the granulomatous lesions observed in this mycosis~ and the capacity of FI to activate the complement system may explain, at least in part, this phenomenon. The aim of our study was to investigate differences that might exist in the activation of human complement system by FI fractions from four different strains of P. brasiliensis. Strains HC and 18 (virulent)~ 265 (avirulent)~ and 9 (intermediate virulence) were used; before the experiments~ the virulence of strains HC and 18 was recovered by in vivo passage in guinea pigs. The four strains of the fungus were processed for purification of the F1 fractions and the activation of human complement system was studied by a kinetic method of hemolytic activity measurement. The incubation of F1 fractions in normal human serum resulted in different degress of inhibition of the hemolytic activity of the alternative pathway (d50 observed were: 193.24 ug (HC); 147.03 ug (18); 113.98 ug (265), and 108.12 ug (9) and classical pathway (d50 observed were: 107.66 ug (HC): 61.76 ug (265); 83.95 ug (18), and 63.14 (9). The FI fraction from the avirulent strain was more efficient in activating both pathways of human complement than the F1 fraction from the virulent strains (HC and 18). These differences in the behavior of the F1 fractions in relation to human complement activation may correlate with the virulence of strains and may contribute to the understanding of the variations observed in the infection induced by different fungal strains.
C4 A N D
BF POLYMORPHISMS
POPULATION AND A GROUP TUSCANY (ITALY).
IN A T U R K I S H
OF ETRURIANS
OF
M. Cuccia 1, A. Brega 2, B. Kirdar 3, A. Cortellazzo, 1 G. Peloso4. 1 Dip. Genetica e Microbiologia, Univ. di Pavia, (Italy) 2 Dip. Biologia e Genetica per le Scienze Mediche, Univ. di Milano (Italy), 3 Dept. of Biology, Bogazici University, Istanbul, (Turkey), 4 Ist. di Medicina Legale, Univ. di Pavia, (Italy) Human HLA complement C4 and BF genes are located on the short arm of chromosome six and their products show extensive genetic polymorphism. The C4A, C4B and BF polymorphisms have been studied in a group of 203 unrelated individuals (111 from Volterra, Tuscany, Italy and 92 taken in Istanbul, Turkey) both at protein and partially at DNA level. The frequency of BFF allele in Turkish population is 26.40%: the two subtypes FB and FA was obtained by isoelectric focusing method and are present respectively in 8.3% and 17.05%. The rare SO allele was present in two individuals of Istanbul (1,2%); the F1 variant was not present as the allele C4A4. The null alleles have frequencies respectively C4AQO 12.94% and C4BQ0 5,29%. Two C4A duplication have been found. BFSO.7 allele reaches a frequency of 3.15% in Tuscany, where the BFS (71.17%) seems low compared with other Northern population of Italy (77.09%). The Turkish group of individuals have been studied also for other polymorphisms of RBC and serum protein: Gliossalase I (GLO I), Phosphoglucomutase 1 (PGM1), Esterase D (EsD), Aptoglobins (HP), Group Specific Component (Gc). Genetic distances among these and other Italian and Albanian populations are calculated.