Jolán Kiss

Neutralizing and enhancing antibodies measured in complement-restored serum samples from HIV-1-infected individuals correlate with immunosuppression and disease

ObjectiveTo study the association between the progression of HIV disease and HIV neutralization and enhancement measured in the presence of human complement. DesignTwo studies were performed: (1) longitudinal measurement of the complement-dependent enhancing antibodies in parallel with T-cell subset determination in 55 serum samples from seven HIV-infected patients, and (2) determination of the titres of neutralizing and enhancing antibodies in stored samples of 21 HIV-asymptomatic patients obtained between 1986 and 1987 and follow-up of the patients until October 1992. MethodsHIV-1 [human T-lymphotropic virus (HTLV)HIB strain, 100 median tissue culture infective dose (TCID50)] was incubated with twofold dilutions of sera in the presence of human complement (final dilution, 1 :4) and added to MT-4 cells. HIV growth was monitored daily for 5 days using the reclustering inhibition and p24 immunofluorescence assays. ResultsA significant negative correlation between the titres of enhancing antibodies and CD4+ cell count was found in longitudinal measurements. In the prospective studies, marked differences were observed between patients with undetectable, low, or high titres of enhancing antibodies in the clinical course of HIV disease: CD4+ cell counts and percentages decreased more rapidly in the high titre group within 3 years. After 5 years, AIDS developed in five out of six patients in the high titre group but only in five out of 15 of the low titre group (P<0.05). A similar difference was observed between patients with and without neutralizing antibodies. ConclusionsMeasurement of HIV neutralization and enhancement in complement-containing serum samples using a complement receptor carrying target may provide data of clinical relevance. Neutralization appears to be associated with a favourable prognosis whereas high titre enhancing antibodies predict rapid progression of HIV disease.

Neutralizing and complement-dependent enhancing antibodies in different stages of HIV infection

Reclustering and indirect immunofluorescence assays on MT-4 cells [carrying both CD4 and complement receptor type 2 (CR2)] were used to measure neutralizing and enhancing antibodies in sera obtained from HIV-1-infected individuals. Heat-inactivated sera were tested before and after mixing 1:1 with fresh seronegative human serum. Using heated samples, neutralizing antibodies were found in 20 out of 20 and 11 out of 19 serum samples of asymptomatic and symptomatic [AIDS, AIDS-related complex (ARC)] HIV-seropositive patients, respectively. In complement-restored samples, neutralizing activity was found in eight sera of asymptomatic patients and in none of the sera of AIDS and ARC patients; enhancing activity could be detected in four and 12 sera, respectively. A significant positive correlation was observed between the titres of neutralizing antibodies measured in the complement-restored samples and the absolute number of CD4+ lymphocytes. These findings indicate that the appearance of complement-dependent enhancing antibodies coincident with the loss of neutralizing antibodies may indicate a poor prognosis in HIV infection.

Changes in Oncogene Expression Implicated in Evolution of Chronic Granulocytic Leukemia from its Chronic Phase to Acceleration

Expression of nine oncogenes was investigated in cell samples from fifteen patients with Philadelphia chromosome (Ph)-positive chronic granulocytic leukemia (CGL) both at diagnosis and at the onset of accelerated phase (AP) of the disease. The bcr-abl fusion gene, the H-ras gene and the c-myb gene were universally expressed. In comparison with the chronic phase (CP) of the disease, an increase in the levels of bcr-abl-, c-myb- and H-ras-related transcripts was found in three, two and three AP samples, respectively. Elevation of the bcr-abl-related message was associated with duplication of the Ph chromosome and amplification of the bcr-abl fusion gene in one AP sample. No CP samples were positive for c-myc or c-sis expression. On the contrary, c-myc and c-sis were expressed in three and four AP samples, respectively. The presence of c-myc-related transcript was associated with trisomy 8 with or without amplification of the c-myc oncogene in leukemia cells of two patients with CGL in AP. No changes of oncogene expression were found in four AP samples. However, we observed deletions of chromosome 13 and 17 or i(17q) in three of them, suggesting that tumor suppressor gene alterations may also be responsible for the development of AP of CGL. Our data indicate that heterogeneous alterations in oncogenes and tumor suppressor genes accompany the evolution of CGL-CP to the AP of the disease.

Placental macrophage contact potentiates the complete replicative cycle of human cytomegalovirus in syncytiotrophoblast cells: Role of interleukin-8 and transforming growth factor-β1

Although syncytiotrophoblast (ST) cells can be infected by human cytomegalovirus (HCMV), in vitro studies have indicated that ST cells do not support the complete viral reproductive cycle, or HCMV replication may occur in less than 3% of ST cells. The present study tested the possibility that placental macrophages might enhance activation of HCMV carried in ST cells and, further, that infected ST cells would be capable of transmitting virus to neighboring macrophages. For this purpose, we studied HCMV replication in ST cells grown alone or cocultured with uninfected placental macrophages. Our results demonstrated that HCMV gene expression in ST cells was markedly upregulated by coculture with macrophages, resulting in release of substantial amounts of infectious virus from HCMV-infected ST cells. After having become permissive for viral replication, ST cells delivered HCMV to the cocultured macrophages, as evidenced by detection of virus-specific antigens in these cells. The stimulatory effect of coculture on HCMV gene expression in ST cells was mediated by marked interleukin-8 (IL-8) and transforming growth factor-beta1 (TGF-beta1) release from macrophages, an effect caused by contact between the different placental cells. Our findings indicate an interactive role for the ST layer and placental macrophages in the dissemination of HCMV among placental tissue. Eventually, these interactions may contribute to the transmission of HCMV from mother to the fetus.

Differential Patterns of Interaction between HIV Type 1 and HTLV Type I in Monocyte-Derived Macrophages Cultured in Vitro : Implications for in Vivo Coinfection with HIV Type 1 and HTLV Type I

The interaction between human immunodeficiency virus type 1 (HIV-1) and human T cell leukemia-lymphoma virus type I (HTLV-I) has generated substantial interest. However, there is disagreement on the in vivo consequences of the double infection. We investigated the interactions between HIV-1 and HTLV-I in monocyte-derived macrophages cultured in vitro. For study, the T cell-tropic strain IIIB and the macrophagetropic strain Ada-M of HIV-1 were used. The HTLV-I was prepared from the supernatants of the virus-producing MT-2 cell line. We found that coinfection of macrophages with T cell-tropic HIV-1 and HTLV-I significantly enhanced HIV-1 replication, whereas double infection of the cells with macrophage-tropic HIV-1 and HTLV-I resulted in marked upregulation of HTLV-I production. Stimulatory interactions between HIV-1 and HTLV-I were mediated by their trans-acting proteins. Results of study on nuclear translocation of proviral DNA showed that the tax gene product of HTLV-I was able to facilitate the nuclear import of the reverse-transcribed HIV-1(IIIB) DNA. In contrast, the HIV-1 Tat protein did not increase the intranuclear trafficking of HTLV-I DNA, which suggests another mechanism for HTLV-I enhancement by the tat gene product. In conclusion, this study provides possible mechanisms whereby coinfection of an individual with HIV-1 and HTLV-I may influence the clinical outcome of double infection.

Comparative study of antibodies that are associated with disease progression in HIV disease

Two types of antibodies which previously were found to be inversely associated with CD4+ cell counts and which may contribute to the progression of HIV disease were measured in parallel in 55 serum samples of 7 longitudinally tested HIV-infected patients (4 homosexual men, 3 haemophilic men) and in 15 serum samples from 15 patients with advanced AIDS. HIV-infection enhancing antibodies were determined in the presence of near-physiologic human complement concentration using a complement receptor type 2 (CR2) carrying HIV-target cell line. IgG and IgA class autoantibodies directed against human IgG-Fab fragments were measured in specific ELISA assays. In agreement with our previous studies obtained in HIV-seropositive haemophilic patients, significant negative correlations were found between CD4+ cell counts and IgG anti-Fab and IgA anti-Fab antibodies (Spearman correlation coefficient r = -0.587, P < 0.0001; and r = -0.269, P = 0.024, respectively). A significant positive correlation was observed between complement-dependent enhancing antibodies and IgA anti-Fab antibodies (r = 0.408, P = 0.003), whereas the correlation with IgG anti-Fab antibodies was only weak (r = 0.288, P = 0.034). Serum samples with high titres of complement-dependent enhancing antibodies had almost 3 times higher IgA anti-Fab autoantibody activity than sera with low titres (P = 0.0038). Our findings indicate that the two disease markers in HIV disease, enhancing antibodies and autoantibodies directed against the Fab moiety of IgG, are not identical. However, anti-Fab antibodies may contribute to complement-dependent HIV infection enhancement.

Demonstration of HTLV-Related Pro viral DNA Sequences and Antibodies Reactive with HTLV Internal Proteins in an Hungarian Patient with Sézary Syndrome

DNA sequences distantly related to the proviral DNA of HTLV-I were found in the leukemic cells of a Hungarian patient suffering from Sézary syndrome. Serum samples from the patient contained antibodies reactive with the internal core polypeptides of HTLV-I and HTLV-II, but not with the env gene encoded type-specific HTLV antigens. The husband and daughter of the patient also had antibodies of the same specificity. These findings suggest the presence of a virus distantly related to HTLV-I and HTLV-II.

Role of interleukin-8 and transforming growth factor-beta1 in enhancement of human cytomegalovirus replication by human T cell leukemia-lymphoma virus type I in macrophages coinfected with both viruses.

Human cytomegalovirus (HCMV) is one of the most frequent opportunistic agents causing severe illness in chronic human T cell leukemia-lymphoma virus type I (HTLV-I) infection. Our previous studies have shown that coinfection of macrophages with HCMV and HTLV-I significantly enhances HCMV replication, resulting in release of infectious HCMV from dually infected cells. We found that double infection of macrophages with HCMV and HTLV-I induced a rapid production of substantial amounts of interleukin-8 (IL-8) and transforming growth factor-beta1 (TGF-beta1). Results of transfection studies demonstrated that the tax gene product of HTLV-I was able to induce secretion of IL-8 and TGF-beta1. In addition to its cytokine-inducing effect, the Tax protein could interact with HCMV synergistically to result in production of much higher levels of IL-8 and TGF-beta1 than expected on the basis of their separate activities. Treatment of dually infected macrophage cultures with neutralizing antibodies to IL-8 and TGF-beta1 led to a nearly 1000-fold decrease in release of infectious HCMV from coinfected cells. Similar results were obtained when anti-IL-8 and anti-TGF-beta1 treatments were combined in macrophage cultures transfected with the tax gene before HCMV infection. Our results suggest that the stimulatory effect of HTLV-I Tax protein on HCMV replication in coinfected macrophages is largely mediated by high levels of IL-8 and TGF-beta1 production.

Co-expression of c-abl and c-myb oncogenes in Philadelphia chromosome-negative, bcr-negative chronic myeloid Leukaemia

Three cases of Philadelphia (Ph) chromosome-negative, bcr-negative chronic myeloid leukaemia (CML) have been investigated for oncogene expression by Northern blot and cytoplasmic RNA dot blot hybridization. Considerably high levels of expression of c-abl and c-myb were observed in all cases. In the Ph-negative cells the normal 6.0 and 7.0 kb c-abl and 3.8 kb c-myb transcripts were found. No amplification of c-abl or c-myb oncogenes was detected in the DNAs of Ph-negative CML cells. Data suggest that co-operation between the overexpressed c-abl and c-myb oncogenes is causally related to Ph-negative bcr-negative CML.

Antiretroviral immune response and plasma interferon in different phases of chronic granulocytic leukemia.

Forty patients with chronic granulocytic leukemia (CGL) were tested for antibodies and lymphocytes reacting with gibbon ape leukemia virus (GaLV) and baboon endogenous virus (BaEV) antigens as well as for plasma interferon levels. Antibodies reacting with envelope antigens of GaLV and BaEV were found frequently and in high titers in patients with the quiescent phase of CGL but rarely and in low titers in the accelerated and blastic phase of the disease. Results of radioimmunoprecipitation studies were in concordance with those obtained in virus neutralization experiments. Cellular and humoral cytotoxic activity of blood plasma and lymphocyte samples against autologous tumor cells showed a similar phase-specific distribution. Most of these activities could be blocked by GaLV and BaEV gp70 antigens. Elevated plasma interferon (IFN)-alpha levels were found in the quiescent and accelerated phase of CGL, whereas no significant differences could be detected between IFN levels of patients with the blastic crisis of CGL and those of the control persons. Follow up studies of four patients confirmed this stage-specific distribution of antiretroviral immune and interferon response.