Biomedical subjects

E K Thomas

Publications and source records attributed to E K Thomas.

At least 37 records · Page 2Linked to original sources

PubMed1999

Flt3-ligand administration after radiation therapy prolongs survival in a murine model of metastatic lung cancer.

An ineffective tumor-specific immune response from inadequate/incompetent antigen presentation could contribute to the failure in tumor control and its dissemination. Dendritic cells (DCs) have been shown to present antigen from apoptotic cells. We hypothesized that Flt3-ligand (Flt3L) therapy, which expands DCs in vivo, in combination with local tumor radiotherapy (RT), should improve antigen presentation from dying, irradiated tumor cells. RT + Flt3L reduced pulmonary metastases in a murine model of Lewis lung carcinoma and significantly improved survival in C57Bl/6 mice with established footpad tumors. Mice treated with Flt3L alone showed delayed tumor growth but eventually succumbed to tumor progression. The combination therapy of RT + Flt3L failed to impact survival in immunodeficient athymic mice, implicating the role of T cells in prolonging survival. These results support an attractive strategy of sequential RT and immunotherapy with Flt3L to enhance tumor antigen presentation, which may produce therapeutic responses against disseminated cancer and improvement in survival.

Animals↗

PubMed1999

Dendritic cell secretion of IL-15 is induced by recombinant huCD40LT and augments the stimulation of antigen-specific cytolytic T cells.

Dendritic cells (DC) are professional antigen-presenting cells which stimulate strong proliferative and cytolytic T cell responses. Stimulation of CD40 on dendritic cells by its ligands and anti-CD40 antibodies induces maturation and enhances DC stimulatory ability. In order to understand the mechanism by which ligand:CD40 interactions augment DC function, we assessed the role of T cell stimulatory cytokines IL-12 and IL-15 in the function of DC stimulated with soluble trimeric CD40L, a recombinant fusion protein incorporating three covalently linked extracellular CD40L domains (huCD40LT). Peripheral blood derived DC treated with huCD40LT and/or IFN-gamma were used to stimulate T cell responses in vitro to specific antigens. DC treated with huCD40LT or IFN-gamma/huCD40LT stimulated enhanced T cell proliferation to CASTA, a soluble protein from C. albicans, induced T cells with augmented antigen-specific lysis, and increased the yield of antigen-specific IFN-gamma-producing T cells. IL-15 production by DC was enhanced in cultures treated with huCD40LT and correlated with expansion of antigen-specific cytolytic T cells. Addition of a neutralizing anti-IL-15 monoclonal antibody inhibited the expansion of viral and tumor antigen-specific T cells stimulated by IFN-gamma and huCD40LT-treated DC. In contrast, this enhanced stimulatory ability of DC did not appear to depend on synthesis of IL-12 since huCD40LT treatment stimulated the generation of antigen-specific cytokine producing and cytolytic T cells without increased IL-12 production. Addition of anti-IL-12 monoclonal antibody did not inhibit expansion of these cells. These data suggest that production of IL-15 but not IL-12 is an important factor in the enhanced immunostimulatory ability of huCD40LT-treated DC.

Antigens↗

PubMed1999

Differential effects of CD40 ligand/trimer stimulation on the ability of dendritic cells to replicate and transmit HIV infection: evidence for CC-chemokine-dependent and -independent mechanisms.

The role of exogenous stimulation of CD40 by CD40 ligand (CD40L) in dendritic cell (DC) maturation, CC-chemokine production, and CCR5 receptor expression was examined using a soluble trimeric CD40L agonist protein (CD40LT). Stimulation of monocyte-derived DCs with CD40LT enhanced the production of the CC-chemokines macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, and RANTES and diminished surface expression of CCR5. Based on these findings, the functional role of CD40LT stimulation on the ability of DCs to replicate and transmit HIV viral infection was studied. The addition of CD40LT to cocultures of naive CD4+ T cells and autologous DCs (T/DC) infected with the macrophage-tropic isolate, HIVBaL, caused a striking reduction in reverse transcriptase (RT) activity after 10 and 14 days of culture. The addition of a mixture of Abs against CC-chemokines abrogated the decrease in RT activity, demonstrating that the inhibitory effect mediated by CD40LT was CC-chemokine-dependent. In contrast, the presence of CD40LT in T/DC cocultures infected with the T cell-tropic isolate, HIV IIIB, caused an increase in RT activity that was CC-chemokine-independent. Of note, CD40LT stimulation also inhibited RT activity in cultures containing macrophage-tropic virus (HIVBaL)-infected DC only. However, in contrast to the results seen in the T/DC cocultures, CD40LT stimulation inhibited RT activity in cultures of DCs alone in a CC-chemokine-independent manner. Together, these results show that CD40LT stimulation of DCs suppresses HIV replication and transmission to CD4+ T cells by two potentially different mechanisms.

CD40 Antigens↗

PubMed1999

Dendritic cells derived in vitro from acute myelogenous leukemia cells stimulate autologous, antileukemic T-cell responses.

We have previously reported that leukemic dendritic cells (DC) can be generated ex vivo from myelomonocytic precursors in chronic myelogenous leukemia. In this study we report the generation of DC from acute myelogenous leukemia (AML) cells and their potent ability to stimulate leukemia-specific cytolytic activity in autologous lymphocytes. DC were generated in vitro using granulocyte-macrophage colony-stimulating factor +interleukin-4 in combination with either tumor necrosis factor-alpha or CD40 ligand (CD40L). Cells from 19 AML patients with a variety of chromosomal abnormalities were studied for their ability to generate DC. In all but 1 case, cells with the morphology, phenotypic characteristics, and T-cell stimulatory properties of DC could be generated. These cells expressed high levels of major histocompatibility complex class I and class II antigens as well as the costimulatory molecules B7-2 and ICAM-1. In three cases these cells were determined to be of leukemic origin by fluorescence in situ hybridization for chromosomal abnormalities or Western blotting for the inv(16) fusion gene product. Autologous lymphocytes cocultured with AML-derived DC (DC-AL) were able to lyse autologous leukemia targets, whereas little cytotoxicity was noted against autologous, normal cells obtained from the patients during remission. We conclude that leukemia derived DC may be useful for immunotherapy of many AML patients.

Acute Disease↗

PubMed1999

Salmonella efficiently enter and survive within cultured CD11c+ dendritic cells initiating cytokine expression.

While Salmonella infects macrophages, this cell population may not be the only one important for disseminating intracellular bacteria from mucosal sites. Dendritic cells (DC) are present in the Peyer's patches and are mobilized following stimulation. Such characteristics would seem to be ideal for the dissemination of an intracellular, mucosal pathogen. However, it has been difficult to obtain sufficient numbers of DC to assess their ability to harbor Salmonella or to monitor DC in vivo. In the present study, this problem has been addressed by expanding DC in vivo using flt3 ligand, followed by the purification of CD11c+ cells using antibody-coated magnetic beads or by fluorescence-activated cell sorting. Salmonella dublin were found to be efficiently internalized, and to survive and replicate within purified CD11c+ DC, and also in CD11c+, CD8alpha+ or CD11c+, CD11b+ DC subpopulations. The ability of Salmonella to enter DC is of similar magnitude to that reported for macrophages, suggesting that this cell population could be an important host cell for dissemination of this pathogen from mucosal sites. Furthermore, infected DC responded to Salmonella by secretion of IL-1, IL-6 and IL-12. As such, these cells may be important sources of these cytokines during the host response against Salmonella infection.

Animals↗

PubMed1999

CD40-CD40 ligand interactions augment survival of normal mice, but not CD40 ligand knockout mice, challenged orally with Salmonella dublin.

Interactions between CD40 expressed on macrophages and CD40 ligand expressed on T lymphocytes can be an important signal for optimal macrophage activation. Previous studies have demonstrated that the optimal response against certain intracellular pathogens (e.g., Crytosporidium and Leishmania spp.) by macrophages requires CD40-CD40 ligand interactions. However, this finding is not universal, since two recent reports utilizing CD40 knockout mice have shown no such contribution to the protective immune response against Mycobacterium tuberculosis or Histoplasma capsulatum. We demonstrate here that CD40-CD40 ligand interactions are significant events in the protective response against the intracellular pathogen Salmonella dublin in normal mice but not for animals genetically deficient in CD40 ligand expression. Treating BALB/c mice exogenously with a CD40 agonist (i.e., soluble trimeric CD40 ligand) increased resistance against a lethal, orally administered dose of S. dublin. Conversely, in vivo administration of a monoclonal antibody against CD40 ligand to block endogenous CD40-CD40 ligand interactions resulted in a decreased resistance to salmonellosis. In contrast, CD40 ligand knockout mice demonstrated no increased susceptibility to salmonellosis. In vitro treatment of Salmonella-infected macrophages from BALB/c mice with soluble trimeric CD40 ligand resulted in an elevated production of interleukin 12p70 by these cells, suggesting a mechanism whereby CD40-CD40 ligand interactions might enhance protective immune responses to this pathogen. Taken together, these studies strongly suggest that CD40-CD40 ligand interactions in normal mice play an important protective role in immune responses against the gram-negative, intracellular pathogen S. dublin.

Animals↗

PubMed1998

Interleukin (IL)-15 enhances antibody-dependent cellular cytotoxicity and natural killer activity in neonatal cells.

Interleukin (IL)-15 is a novel cytokine that is very similar to IL-2 in receptor specificity and biological activities. We compared the ability of IL-15 and IL-12 to enhance the cytotoxicity of neonatal (cord blood) and adult mononuclear cells (MNC) in both natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) assays. Incubation with IL-15 (10 ng/ml) or IL-12 (1 ng/ml) for 18 h enhanced the NK activity (using K562 target cells) of both cord and adult MNC, increasing cord cell cytotoxicity threefold. Similar enhancement was seen in ADCC assays using erythrocyte targets and NK-resistant CEM cells coated with HIV gp-120 antigen. Incubation of cord cells with IL-15 or IL-12 for 1 week increased both NK and ADCC, although the combination produced less of an effect than either cytokine alone. IL-15 also increased the percentage of CD16+/CD56+ cells after 1 week incubation. This enhancement of NK and ADCC activities and the number of NK cells by IL-15 suggests it may be clinically useful in treating immunodeficient patients.

Adjuvants, Immunologic↗

PubMed1998

Effect of interleukin (IL)-12 and IL-15 on activated natural killer (ANK) and antibody-dependent cellular cytotoxicity (ADCC) in HIV infection.

The ability of IL-12 and IL-15 to enhance natural killer (NK) activity and antibody-dependent cellular cytotoxicity (ADCC) of mononuclear cells (MNCs) from HIV+ children and their mothers was investigated. MNCs from HIV+ patients were deficient in NK and ADCC activity compared to control MNCs against several target cells. Overnight incubation with IL-15 or IL-12 augmented NK activity of MNCs from both patients and controls, and the combination of IL-12 and IL-15 resulted in the greatest enhancement. ADCC in HIV+ patients against gp120-coated CEM.NKR cells or chicken erythrocytes could also be enhanced by IL-2 or IL-15 in overnight cultures. Culturing MNCs with either IL-2 or IL-15 for 1 week increased the NK activity in patients to levels of controls treated with these cytokines. However, the response to the combination of IL-12 and IL-15 was less than that to IL-15 alone in 1-week cultures. Culturing MNCs with IL-2 and IL-15 for 1 week also increased the percentage of CD16+/CD56+ cells in both patients and controls. Thus, IL-15 can restore the deficient NK activity in patients and may be a candidate for immunomodulative therapy in HIV+ patients.

Adult↗

PubMed1998

Elevated levels of biologically active soluble CD40 ligand in the serum of patients with chronic lymphocytic leukaemia.

Chronic lymphocytic leukaemia (CLL) is an indolent lymphoproliferative disorder manifested by low growth fraction and prolonged survival of the malignant cells. The mechanisms that enable CLL cells to live longer and to resist apoptosis remain unclear. Because the malignant CLL cells express CD40 and Fas receptors, which can transduce cell-survival and cell-death signals, we examined the role of CD40 in the growth regulation of CLL cells and its interaction with Fas-mediated and fludarabine-induced apoptosis in vitro. Primary CLL cells underwent spontaneous apoptosis in culture, which was enhanced by exogenous human Fas ligand (FasL) or fludarabine. Exogenous CD40L rescued CLL cells from spontaneous apoptosis in a dose-dependent manner, and caused CLL cells to resist apoptosis induced by FasL or fludarabine. Patients' autologous plasma rescued CLL cells from spontaneous apoptosis, an effect that could be reversed with anti-CD40 ligand (CD40L) antibodies. The levels of soluble CD40 ligand in the sera of 51 CLL patients and 55 healthy donors were determined by enzyme-linked immunosorbent assay. The mean soluble CD40L level in normal donors was 0.29 ng/ml compared to a mean value of 0.80 ng/ml in CLL patients (P < 0.001). CD40L up-regulated bcl-X(L) mRNA but not bcl-2 in CLL cells within 3-6 h in culture. Our results demonstrated that serum of patients with CLL contained elevated levels of biologically active soluble CD40L, and that CD40L can prolong survival of CLL cells and mediate their resistance to FasL and fludarabine in vitro.

Adult↗

PubMed1998

Comparative analysis of murine dendritic cells derived from spleen and bone marrow.

In order to improve upon preclinical tumor vaccine strategies that employ dendritic cells (DC), we now have compared short-term cultures of spleen- and GM-CSF/IL-4-stimulated bone marrow (BM) to determine if differences exist in phenotype and function of murine DC derived from primary and secondary hematolymphoid organs. Although cultures of BM contained a lower percentage of DC compared to spleen, their capacity to stimulate a primary allogeneic mixed leukocyte reaction (MLR) and to uptake fluorescent dextran was substantially greater. In addition, the overall yields of DC per animal was at least twofold greater from BM compared to spleen. Cultures of BM harvested at day 3, 6, or 9 stimulated comparable levels of primary allo-MLR on a per-cell basis. However, there was a consistent loss (at least twofold) of all cells occurring beyond day 6 as compared with cell yields from earlier time points. Importantly, we also improved on methods to rapidly obtain highly enriched DC (> 90%) from BM, which has obviated the reported prior need for complex antibody and complement treatments to remove contaminating mature T and B lymphocytes, Ia-bearing cells, and granulocytes before DC generation. In contrast, although similar purity of DC with similar phenotype and function could be obtained from the spleen, substantial loss in yield occurred, suggesting a further difference in DC between the two tissue sources. The overall yield of DC derived from spleen and BM cultures could be substantially increased by in vivo pretreatment of the donor animals with recombinant Flt3-L. Collectively, these studies demonstrate that notable differences exist in DC preparations derived from spleen vs. BM and that BM provides the preferred source of DC that can be rapidly enriched to high purity for use in further vaccine development.

Adjuvants, Immunologic↗

PubMed1997

Human immunodeficiency virus (HIV) type-1 GP120-specific cell-mediated cytotoxicity (CMC) and natural killer (NK) activity in HIV-infected (HIV+) subjects: enhancement with interleukin-2(IL-2), IL-12, and IL-15.

Cell-mediated cytotoxicity (CMC), as mediated by cytophilic antibody to human immunodeficiency virus (HIV) antigens, may be an important defense in HIV-infected (HIV+) patients in response to the virus. In this study the ability of interleukin (IL)-2, IL-12, and IL-15 to enhance natural killer (NK) and gp120-specific CMC of mononuclear cells (MNCs) from HIV+ children and adults was examined. NK activity against K562 cells was deficient in HIV+ patients compared to controls and could be enhanced by IL-2, IL-12, or IL-15, with the combinations of IL-2 + IL-12 and IL-12 + IL-15 producing more cytotoxicity than individual cytokines. Gp120-specific CMC was significantly higher in patients than in controls. It could be increased by IL-2, IL-12, and IL-15 and further by combining IL-2 and IL-12. When an exogenous source of antibody in the form of hyperimmune HIV-specific immunoglobulin (HIVIG) was present, the response of control MNCs was much higher than that of patients, although gp120-specific cytotoxicity of patients' MNCs was significantly enhanced (two- to threefold) by the addition of HIVIG. This increment in cytotoxicity due to HIVIG, however, could not be further augmented by cytokines in controls or patients. Our findings suggest multiple cytokine administration to boost NK cell function, together with passive immunotherapy, might offer a new therapeutic approach to benefit HIV+ patients.

Adolescent↗

PubMed1997

Activity of TNF-related apoptosis-inducing ligand (TRAIL) in haematological malignancies.

T-cell cytotoxicity is primarily mediated by two cell surface proteins, Fas ligand (FasL) and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and intracellular perforin and granzyme granules. FasL-deficient and perforin-deficient T lymphocytes maintain cytotoxicity but fail to induce graft-versus-host disease (GVHD) when transplanted into mice. suggesting that GVHD and graft-versus-tumour (GVT) effects can be dissociated, and that TRAIL is not involved in the pathogenesis of GVHD. Because TRAIL could mediate a favourable GVT effect it became important to study the spectrum of its activity and to investigate factors that can dissociate its expression from FasL. TRAIL induced apoptosis in 11/41 (27%) tumour specimens of haematological origin compared to 16/41 (39%) induced by FasL. Although eight specimens were sensitive to both FasL and TRAIL, no synergism was observed between these two ligands. TRAIL induced apoptosis in a dose and time dependent manner with an ED50 of 0.5 microg/ml and EDmax of 1 microg/ml. TRAIL activity was not reduced by the over-expression of the multidrug resistant (MDR) protein, and was not enhanced by 9-cis retinoic acid (RA), which can down-regulate bcl-2 protein. Both ligands were simultaneously up-regulated in normal peripheral blood lymphocytes in response to IL-2, IL-15 and anti-CD3 antibody, whereas IL-10 had no effect. Together, our data show that (1) TRAIL can mediate cell death in a variety of human haematological malignancies, (2) resistance to TRAIL is not mediated by MDR protein, (3) the lack of synergy between TRAIL and FasL suggests that either one is sufficient to mediate T-cell cytotoxicity, and (4) within the panel of cytokines tested, the expression of TRAIL and FasL could not be dissociated.

Apoptosis↗

PubMed1997

CD30 ligand in lymphoma patients with CD30+ tumors.

PURPOSE: CD30 ligand (CD30L), which is expressed on resting B and activated T lymphocytes, can induce cell death in several CD30+ cell lines. Patients with CD30+ tumors (Hodgkin's disease and Ki-1+ non-Hodgkin's lymphoma) frequently have elevated soluble CD30 (sCD30) levels in their serum, which correlates with a poor prognosis. The role of sCD30 in protecting tumor cells from CD30L-mediated cell death and the pattern of CD30L expression on human peripheral-blood lymphocytes (PBLs) of normal donors and patients with CD30+ tumors are investigated. MATERIALS AND METHODS: CD30L surface protein expression was determined by two-color flow cytometry on PBLs of patients with CD30+ tumors and normal individuals. CD30L levels were determined on subsets of PBLs before and after stimulation with phytohemagglutinin (PHA), anti-CD3 antibody, or CD40L. sCD30 was measured by enzyme-linked immunosorbent assay (ELISA). The apoptotic activity of membrane-bound CD30L was tested in a CD30+ cell line by the annexin V-binding method. RESULTS: Unstimulated T lymphocytes of normal donors and patients with lymphoma rarely expressed CD30L surface protein, but were able to express it after stimulation with PHA or anti-CD3 antibody. Resting B cells of patients with CD30+ tumors had lower levels of detectable surface CD30L compared with normal donors (mean, 55% and 80.6%, respectively; P = .0008). Patients with high levels of serum sCD30 had lower detectable levels of CD30L on their PBLs (R2 = .72, P = .0008) and exogenous sCD30 blocked membrane-bound CD30L-mediated apoptosis in a CD30+ cell line. CONCLUSION: In patients with CD30+ tumors, sCD30 can decrease the availability of CD30L on PBLs. Blocking the apoptosis-inducing activity of CD30L by its soluble receptor may explain how CD30+ tumors escape immunosurveillance and may be related to the reported poor prognosis of patients who have elevated sCD30 levels.

Adolescent↗

PubMed1996

IL-15 stimulates the expansion of AIDS virus-specific CTL.

It has been assumed that the maturation of pre-CTL to virus-specific effector CTL is dependent upon IL-2-mediated T cell triggering through the IL-2R. In view of its similarity to IL-2 in its effects on immune cells, we sought to determine whether IL-15 can induce the expansion of AIDS virus-specific pre-CTL to mature CTL. PBL of SIV(mac)-infected rhesus monkeys or HIV-1-infected humans have previously been shown to expand to effector CTL when cultivated with a predicted CTL epitope peptide and rIL-2. We now demonstrate that rIL-15 facilitates this expansion of effector CTL. In fact, rIL-15-driven expansion of virus-specific CTL occurs in the presence of IL-2-neutralizing or anti-IL-2R Abs, indicating that this cellular maturation can occur in an IL-2-independent fashion. These studies suggest a mechanism by which CTL may be capable of expanding in vivo in the absence of IL-2 and functional CD4+ T lymphocytes.

Amino Acid Sequence↗

PubMed1996

Activation of antigen-induced lymphocyte proliferation by interleukin-15 without the mitogenic effect of interleukin-2 that may induce human immunodeficiency virus-1 expression.

The newly identified cytokine, IL-15 enhanced antigen-induced proliferation of PBMC obtained from HIV-1-seropositive subjects. When compared to IL-2 which enhanced both spontaneous and antigen-induced lymphocyte proliferative responses, IL-15 rarely increased spontaneous lymphocyte proliferation. Additionally, in cultures of lymphocytes obtained from 15 HIV-1-infected patients with < 300 circulating CD4- lymphocytes/microliter IL-15 induced significant HIV-1 expression (46, 21, and 71 pg/ml) in only 3 of 15 experiments and IL-2 induced significant HIV-1 expression (range 16- > 5000 pg/ml) in 11 of 15 experiments (P < 0.01, Fischer's exact test). Simultaneous assays of cytokine-induced spontaneous lymphocyte proliferation and HIV-1 expression revealed similar dose-response relationships for induction of HIV-1 and lymphocyte proliferation by IL-2. Thus, IL-15 helps to correct the impaired proliferative response of CD4+ lymphocytes from HIV-1-infected persons without the mitogenic effect of IL-2 that also may induce HIV-1 expression.

Adult↗

PubMed1996

Anti-idiotypic antibody to the V3 domain of gp120 binds to vimentin: a possible role of intermediate filaments in the early steps of HIV-1 infection cycle.

Although the CD4 molecule is the major cellular receptor for human immunodeficiency virus (HIV), several lines of evidence suggest participation of additional molecules that are engaged after the binding of HIV to the CD4 receptor and that may facilitate viral entry into the target cell. Some of the post-CD4 binding, perfusion events involve the third hypervariable region (V3 loop) of the viral envelope protein gp120. To identify cellular proteins that interact with the V3 loop, we chose as a probe an antiidiotypic monoclonal antibody (MAb), anti-id2, which was prepared against the neutralizing MAb 110.4 that binds the V3 domain in the envelope glycoprotein gp120 of the LAI isolate of HIV-1. Anti-id2 reacted specifically with a 55- to 60-kDa protein in human T cell and monocytoid cell lines, and in a mouse melanoma cell line. This protein was identified immunologically and by protein sequence analysis as vimentin, an intermediate filament protein of lymphoid and other cells of mesodermal origin. Antiserum raised against vimentin inhibited nuclear translocation of HIV-1 DNA following infection of monocytes and CD4+ T cells with live virus, and reduced the amount of HIV-1 gag-specific RNA in the nuclei of monocytes following inoculation with HIV-1 pseudovirions. These data suggest that vimentin may participate in the early steps of HIV-1 replication, perhaps during the uptake of HIV-1 preintegration complexes into the nuclear compartment.

Animals↗

PubMed1994

Dual specificity of a monoclonal anti-idiotypic antibody for HIV-1 neutralizing monoclonals 110.3 and 110.4 as well as the V3 loop of gp120.

Monoclonal antibodies (MAbs) 110.3 and 110.4 bind an epitope at the tip of the third hypervariable region (V3) of the envelope protein gp120 of human immunodeficiency virus type 1 (HIV-1). These MAbs inhibit HIV-induced syncytium formation and neutralize cell-free virus infection. Anti-idiotypic MAb alpha-id8, generated against 110.3, was found to mimic the V3 loop of gp120, as demonstrated by competition ELISA and by the generation of anti-anti-idiotypic sera which bound gp120 and a peptide representing the tip of the V3 loop. Interestingly, alpha-id8 itself also reacted specifically with both gp120 and the V3 loop peptide. Thus, alpha-id8 both mimics and binds directly to the V3 loop, suggesting that the V3 loop of gp120 may associate with itself.

Amino Acid Sequence↗

PubMed1993

Variable region gene utilization and mutation in a group of neutralizing murine anti-human immunodeficiency virus type 1 principal neutralizing determinant antibodies.

The heavy (VH) and light (VL) chain variable region nucleotide sequences of four neutralizing anti-human immunodeficiency virus type 1 (HIV-1) murine monoclonal antibodies (mAbs) were determined. These mAbs bind to native gp120, recombinant gp120, and a linear HIV-1 principal neutralizing determinant (PND) peptide that spans amino acid 308-328. Three mAbs that bind to the same linear determinant, 110.3, 110.4, and 110.5, all use the same VL gene elements, a VK21 gene and JK2. These three mAbs also share the same VKJK junctional diversity and specific somatic mutations. They have identical VL immunoglobulin gene rearrangement patterns on Southern blot. Two of the antibodies, 110.4 and 110.5, also use the same VH gene elements, SB32-D-JH4, and have identical VD and DJ junctions and N sequences. Two different anti-HIV-1 PND murine mAbs reported by others, BAT123 and 0.5 beta, also use VK21-JK2, and BAT123 also uses the SB32 VH gene element. Although 110.3 uses the same VL region gene as 110.3 and 110.4, it uses a different VH gene that appears to be a member of the 7183 VH family. 110.6, an mAb that recognizes a discrete, overlapping PND compared to 110.3, 110.4, and 110.5, uses entirely different VH and VL gene elements and has unique immunoglobulin VH and VL rearrangement patterns. Our data, taken together with reports of the BAT123 and 0.5 beta mAb sequences, suggest that the murine antibody response to HIV-1 PND may be restricted to a small subset of VH and VL gene elements.

Amino Acid Sequence↗