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Biomedical subjects

T F Schulz

Publications and source records attributed to T F Schulz.

131 records · Page 8Linked to original sources
PubMed1983

Coupling of C3b to erythrocytes by disulfide bond formation: preparation of EC3b for hemolytic and complement receptor assays.

We describe a new method of preparing C3-coated erythrocytes by coupling C3 to thiol-activated erythrocytes. The procedure involves three steps. Firstly, sheep erythrocytes were treated with N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) to introduce 3-(2-pyridyldithio) propionyl residues into membrane proteins. Secondly, C3 was cleaved with trypsin or CoVF, Bb enzyme to obtain C3b exposing the SH group (C3b-SH). Finally, the C3b-SH was coupled to the thiol-activated erythrocytes (TA-E) through thiol/disulfide exchange to form the TA-EC3b conjugate. E coated with C3d was prepared by treating TA-EC3b with KSCN inactivated serum and plasmin. Studying the rosette formation between TA-EC3b or TA-EC3d and cells expressing C3b (CR1) and C3d (CR2) receptors and the inhibition thereof with anti-CR1 and anti-CR2 antibodies as well as with C3-sheep E membrane protein complexes, we found that TA-EC3b and TA-EC3d bound exclusively to CR1 and CR2, respectively. In addition, TA-EC3b like EAC1423b bound factors B and H as tested by hemolytic and direct binding assays. The advantage of TA-EC3 for complement receptor and hemolytic assays are the simplicity of the preparation method and the general applicability of the TA-EC3.

Animals↗
PubMed1983

Importance of factors H and I for the adherence of C3b-coated erythrocytes to cells.

The role of cell membrane-associated human factor H for the binding of cell-bound C3b to complement receptor-carrying (CR+) cells was investigated. Pretreatment of CR+ cells with antibodies to factor H inhibited the adherence of C3b-coated red cells to human tonsil lymphocytes (TL) and peripheral blood monocytes (M phi). The C3b receptor reactivity of human polymorphonuclear leucocytes (PMN) was not influenced and the one of Raji lymphoblastoid cells only slightly influenced; iC3b and C3d receptor reactivity was in no case affected. When diisopropylfluorophosphate (DFP) in a concentration of 0.1 mM was present during pretreatment of the CR+ cells with anti H, the antibodies gained the capacity to inhibit the adherence of C3b-coated erythrocytes to Raji cells; this effect was dose-dependent with respect to DFP. In contrast, there was no influence of DFP on the inhibition pattern of anti H in the case of TL and M phi. The adherence of C3b-coated erythrocytes to PMN remained unaffected by anti-H antibodies in the presence of DFP. Polyclonal as well as monoclonal antibodies directed against human factor I inhibited the binding of C3b cells to Raji cells but not to TL. Additionally, when anti I and anti H antibodies were both present, C3b receptor reactivity of Raji cells was inhibited to a larger extent than with either antibody alone; again, TL remained unaffected. Results obtained by washing the Raji cells before and after treatment with anti H and anti I suggest that the respective antibodies act on factor H primarily on the level of the cell membrane and on factor I in the fluid phase.

Animals↗
PubMedDate not supplied

Kaposi's sarcoma in the Gambia, West Africa is less frequent in human immunodeficiency virus type 2 than in human immunodeficiency virus type 1 infection despite a high prevalence of human herpesvirus 8.

OBJECTIVES: To investigate the distribution of Kaposi's sarcoma (KS) cases in patients with human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) infection in the Gambia; to document the prevalence of human herpesvirus 8 (HHV-8) infection in various population groups in the Gambia. STUDY DESIGN/METHODS: A retrospective analysis of KS cases in hospital records at the Medical Research Council (MRC) hospital was performed, along with a cross-sectional survey of HHV-8 prevalence in hospital-based and community-based study population with polymerase chain reaction (PCR) and serologic assays. RESULTS: After adjusting for gender and CD% at the first visit, HIV-1-positive patients were 12.4 times more likely to have KS than were HIV-2-positive patients. The prevalence of antibodies to HHV-8 and the HHV-8 genome was high in both HIV-1-positive and HIV-2-positive patients without KS. The prevalence of antibodies was also high in pregnant women who were HIV-1-positive, HIV-2-positive, or HIV-negative (73%, 83%, and 79%, respectively). CONCLUSIONS: HHV-8 infection is widespread in the Gambia. In addition to immunosuppression and HHV-8 infection, other cofactors specifically related to HIV-1 rather than HIV-2 appear to be involved in the development of KS.

AIDS-Related Opportunistic Infections↗
PubMedDate not supplied

Seroprevalence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8 in several regions of Italy.

OBJECTIVE: To study the seroprevalence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus type 8 (KSHV/HHV-8) in 779 Italian blood donors. STUDY DESIGN/METHODS: Sera were tested for antibodies to a latency-associated nuclear antigen (LANA) and a capsid related protein encoded by ORF65. RESULTS: Among all Italian donors, 17.7% and 18.7% had antibodies to LANA and ORF65 protein, respectively, and 24.1% had antibodies to at least one antigen. KSHV/HHV-8 seroprevalence was higher in the Po valley and in Sardinia than close to the sub-Alpine Veneto region, Tuscany, or Apulia. KSHV/HHV-8 seroprevalence was almost equally distributed between men and women but increased in the older age groups. CONCLUSIONS: The regional differences and age distribution in seroprevalence agree partially with the incidence of classic KS in Italy. The rarity of classic KS in KSHV/HHV-8-infected subjects and the equal gender distribution of seroprevalence suggest that other cofactors may contribute to KS development in human immunodeficiency virus type 1 (HIV-1)-uninfected individuals.

Adolescent↗