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Coronavirus disease 2019 is associated with clinical symptoms including severe inflammatory syndrome and a higher expression of angiotensin II. As a pro-inflammatory mediator, the physiologic effects of angiotensin II are mediated by a G-protein coupled receptor, termed AT1R. Following binding, AT1R initiates the process of signal desensitization necessary to maintain cellular homeostasis. At the cellular level, this function occurs via the G protein-dependent signaling and the phosphorylation. We describe amino acids similarities between SARS COV-2 nonstructural protein (NSP8) which is associated with intracellular membranes and AT1R key sites. Since abnormal activation of AT1R receptor leads to a number of physiological disorders, we hypothesize that SARS COV-2 might further interfere with the angiotensin II receptor functions.

Aids is characterized by progressive T cell depletion, immune cells dysfunctions and interferon responsiveness that are driven by chronic activation. Antiretroviral therapy (ART), although effective in improving the survival of HIV-1- infected individuals, has not been able to reconstitute the adaptive immunity. However, ART is neither able to eradicate the virus nor has sufficient immune-modulatory effects to control viral infection. This situation points out the dilemma that current HIV therapy can maintain the disease in a resting state, but not eliminate it. We have described the use of novel chemical agents able to restore T-cell survival by inducing cytokines production. More recently, we suggested a complementary therapy based on the chemical induction of endogenous  / interferon. We suggest that a therapeutic strategy based upon chemical immune restoration associated with type 1 Interferon (IFN- / ) might represent a mean for HIV cure. This finding may be vital for future therapeutic approaches in AIDS disease and the immune reconstitution. Understanding these process can lead to a range of new therapeutic interventions.

Pleiotrophin (PTN) is a polypeptide that belongs to a family of heparin-binding growth factors; it displays mitogenic activity for a wide variety of cells. In a previous study, we reported that PTN induces the stimulation of expression of inflammatory cytokines, including tumour necrosis factor alpha (TNF-alpha), interleukin (IL)-1beta and IL-6, in quiescent human peripheral blood mononuclear cells (PBMCs) through B-lymphocyte binding. These results emphasize the importance of PTN in the regulation of inflammatory processes. Moreover, using in vitro infection of PBMCs or using PBMCs from AIDS patients, we showed that PTN was sufficient to induce human immunodeficiency virus type 1 (HIV-1) replication. Moreover, neutralization of TNF-alpha, IL-1beta and IL-6 suppressed HIV replication in PTN-stimulated PBMCs. As these cytokines are potent upregulators of virus expression, these results should prove useful in investigating the role of PTN as a host factor in the regulation of pathological disorders in HIV-1 infection. Identification of this host factor could be important for understanding HIV disease and designating therapeutic approaches.

The immunological cross-reactivity of several peptides with specific pattern-property characteristics related to the epitopes of human immunodeficiency virus type 1 (HIV-1) gp160/ 120 envelope proteins has been investigated. Proteins with similar primary structures can be expected to show functional or topographic similarities, such as specific epitopes which may cross-react with antibodies derived from the immunisation of animals with other members of the same protein family. These structure-function characteristics may be revealed as periodicities derived from presentations based on the discrete Fourier transformation of the distributions of various physico-chemical amino acid descriptors, constituting the polypeptide backbone and amino acid side-chains of the protein molecule. Such approaches, for example, have permitted prediction of periodicities corresponding to secondary structural motifs, including amphipathic alpha-helices and beta-sheets, within protein sequences, and have helped to clarify potential binding sites for ligands, substrates or cofactors with interacting macromolecules. Based on this approach, characteristic periodicities have been identified which represent common Fourier transform spectral properties of the envelope (ENV) gp160/120 glycoproteins from a range of HIV-1 isolates. In addition, similar periodicities have been detected as components of the discrete Fourier transform representation of the corresponding amino acid descriptors of the CD4 binding domain of gp120. Accordingly, we have synthesised several peptides having periodic characteristics in their discrete Fourier transform representations similar to these HIV-1 proteins. These nonhomologous synthetic peptides induced cross-reactive antibodies in New Zealand White rabbits. Polyclonal antibodies raised to one of these peptides reacted with HIV-1 ENV gp120-related proteins, as determined by enzyme-linked immunosorbent assay and Western blotting techniques. These findings provide further evidence for a role of immunological cross-reactivity and molecular biomimicry in the development of peptide-based vaccines directed against viral or bacterial pathogens.

Interferon gamma (IFN-gamma) was previously shown to promote fatty acid (FA) release from adipose tissue (AT). Net lipolysis is an equilibrium between triglyceride breakdown and FA re-esterification. The latter requires activated glyceroneogenesis for glycerol-3-phosphate synthesis and increased cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), the key enzyme in this pathway. We wondered whether glyceroneogenesis and PEPCK-C would be IFN-gamma targets. We injected mice with IFN-gamma, and exposed either AT explants and isolated adipocytes from humans and mice or 3T3-F442A adipocytes to IFN-gamma before monitoring expression of genes involved in lipid metabolism and the metabolic consequences. We show that IFN-gamma induces a large increase in FA release without affecting glycerol output and decreases [1-(14)C]-pyruvate incorporation into lipids, thus demonstrating that FA re-esterification is reduced due to diminished glyceroneogenesis. A series of mRNA encoding proteins involved in FA metabolism remained unaffected by IFN-gamma, while that of PEPCK-C was rapidly and drastically lowered. IFN-gamma effect opposed that of the beta-agonist isoproterenol and of 8-Br-cAMP. In IFN-gamma-treated mice, PEPCK-C gene expression was decreased in AT, but not in liver or kidney. Thus, IFN-gamma exerts a tissue-specific action in rodents and humans, having glyceroneogenesis and the PEPCK-C gene as selective targets to intensify FA release from adipocytes.

Sarcolectin (SCL) is a nonspecific stimulator of cellular DNA synthesis that was found in all animal sera tested to date. It inhibits the established interferon (IFN)-dependent antiviral state, restoring cells to their normal status. In this study, we examined the excretion/secretion of the IFN antagonist SCL in sera from healthy donors and in sera collected during different periods of human immunodeficiency virus type 1 (HIV-1) infection. We followed HIV-1-infected patients during all stages of development (seroconversion, initial and advanced phases of AIDS) and found a significant increase in SCL in sera of HIV-infected patients compared with seronegative subjects used as controls. This increase was established during seroconversion, and then the titers leveled off. In the final stage of the disease, the SCL titer increased again very significantly. We attribute this rapid rise to the virus-dependent destruction of T cells that can no longer be repaired. The high SCL level observed at this final stage, which is most predictive of the disease’ s progression, suggests that the action, rather than the production, of IFN is impaired.

Cytotoxic T cell determinants should be an important component of an anti-human immunodeficiency virus (HIV) vaccine. The epitopes of proteins can be defined with short synthetic peptides for class I-restricted CTLs. An immunodominant CTL epitope from the HIV-1 IIIB envelope protein gp160 comprising 15 amino acids (residues 315-329: RIQRGPGRAFVTIGK) (P18IIIB) has been identified that is recognized by class I MHC molecule H-2d-restricted murine CD8+ CTLs. We have investigated the epitope specificity of anti-HIV-1 CTLs in immunized individuals and we found that the CTL response was restricted by more than one class I MHC molecule, including HLA-A2 and HLA-A3. In the present work, we also show that the response against P18IIIB peptide is restricted by the HLA-A11 molecule in an individual immunized by vaccinia virus expressing gp160 protein. This peptide could thus be recognized in association with different HLA class I allotypes. This work has implications for vaccine strategies, using the P18 peptide.

The cellular immune response to the AIDS virus in healthy individuals immunized with HIV-1 antigens has not yet been entirely understood. Unlike HIV-1 infected patients where direct measurements of anti HIV-1 CTL activities can be readily performed with fresh peripheral blood mononuclear cells, uninfected volunteers immunized against HIV-1 antigens have fewer circulating CTL necessitating an in vitro activation in order to amplify the cytotoxic signal and make it measurable. This study presents experiments where specific CTLs are successfully obtained simply by in vitro infection of PBMCs from HIV-1 Envelope immunized individuals.

Four cardinal immune disorders interacting with each other may promote the progressive T cell depletion and immunosuppression characterizing AIDS. Immune activation of HIV-1 infected T4 cells leads to virus release and premature cell death. Both virus release with its resulting viral load and dead cells are the source of gp120 stimulus. Anergy of non-infected CD4 cells, resulting in cytokine dysregulation may be promoted by impairing the CD4-MHC interaction during CD4 cell activation either directly through the SLWDQ pentapeptide identity with the CD4 molecule and the CD4 binding region or through a gp120-induced autoimmune reaction to CD4. Overproduction of IFNα, the known antiproliferative and cytolytic cytokine may promote in a paracrine manner to neighbouring cells the immunosuppression generated by the lack of IL2 secretion following CD4 cell anergy. Apoptosis of activated non infected T cells could be induced by effector components of the sutoimmune reaction (CTL, Lymphotoxins or Abs?) directed towards the 2 consensus gp120 sequence identity/similarity (INCTR and FYCNST) shared with the APO/Fas molecule. These two sequences are known as immunodominant sites of the gp120. Furthermore, IFNa overproduction may also render circulating memory T cells competent to apoptosis by upregulating the cascade of metabolic events leading to programmed cell death.

CD4 molecules interact with class II major histocompatibility complex molecules as a critical costimulatory signal in CD4+ cell immune activation. CD4 also recognizes a specific region of the human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein gp120 forming a binding site for early stages of HIV-1 infection. We designed two software packages, AUTOMAT and CRITIC, which allowed us to identify similarities between regions of HIV-1 proteins and immunoregulatory protein sequences stored in data banks. In this report we have characterized (i) a pentapeptide, SLWDQ, found in both CD4 and HIV-1 gp120, which surprisingly had remained undetected in these two well-studied molecules until now, and (ii) an HLA sequence corresponding to the putative functional site of H2 I-A. We found that a region of gp120 (residues 254-263) known to be similar to a sequence in HLA class II beta chain overlaps this functional region. We showed experimentally that these two CD4 and HLA peptide segments inhibit CD4+ cell immune activation. There is strong inhibition (50% up to 80%) of immune activation by SLWDQ-containing gp120 segments and a lesser inhibition by the gp120 HLA-homologous segment. In addition, we found that SLWDQ induced in HIV-1-infected individuals a humoral (antibody) and cellular (cytotoxic T lymphocyte) immune reaction. We propose that these HIV-1 gp120 segments, together with the known CD4-binding region, may contribute to the HIV-1-induced immunosuppression by two mechanisms affecting CD4-HLA interaction during T-cell immune activation: autoimmune reaction toward CD4 and direct interference with the CD4-HLA costimulatory signal inducing CD4+ cell anergy with, as a consequence, generation of immunosuppression.

We have designed a computer strategy in order to detect systematically peptidic sites with the potential of interfering with the immune regulatory processes. Applying this software to HIV-1 proteins has led us to unravel a few peptidic sites which could either act directly or be the targets of an auto-immune reaction during HIV-1 infection. We previously reported that the SLWDQ pentapeptide identity with a critical site of CD4 could trigger in HIV-1 infected individuals both an humoral and a cellular autoimmune reaction. In this study, we focused on surprising similitudes unravelled by our software Automat, between HIV-1/2 and another immunoregulatory molecule, the Fas protein which is also called the apoptosis-mediating cell-surface antigen.

Sarcolectin (SCL) is a 55 kDa protein cross-reacting with a cytokeratin 7 monomer found in placental blood, sarcomas and various tissues. It blocks the synthesis of interferon-dependent secondary proteins, induces cell DNA activation and sensitizes cells to viral infection. SCL is a potent promoter of tissue growth. In the present report, we demonstrate that SCL is expressed in the human pituitary gland at the mRNA and protein levels. We show also its presence in human amniotic fluid in high titres while interferon titres is weak. These results allow to postulate a potential role of SCL as a growth factor participating in human foetal development.

HIV-1 antigens generate in man both a humoral and cellular immune reaction. However, in ARC/AIDS patients, the cellular response is inhibited by HIV-1 which induces an antiproliferative (suppressive) effect on activated T cells. To overcome this inhibition and up-regulate the cellular response, we designed a new vaccine strategy directed both against HIV-1 and immunosuppression and we used an immunizing preparation composed of HIV-1 antigens combined with immunoregulatory peptides prepared in a biologically inactivated but immunogenic form. In mice, this preparation induced anti-HIV-1 antibodies and a cell-mediated cytotoxicity directed against H2 restricted cells carrying HIV-1 antigens. HIV-1 vaccine / immunosuppression / HIV-1 peptides.

We have designed two software systems allowing the study of proteins through a comparison to those stored in data banks. The first one, “Automat”, locates in a systematic manner all identities shared by a given protein and the proteins in a data bank. The second, “Critic” enables the selection of specific segments in a given molecule by comparing them with those gathered in a data bank. These sites were termed “critical” since they mostly correspond to functional sites (active sites) of the well-known proteins which were studied with the aid of this program (somatostatin, insulin. IL2, etc). Automat allowed us to reveal homologies between HIV-1 and the CD4, which have remained unsolved until now. These similitudes proved to be critical sites (according to Critic). The putative involvement of these sites in the physiopathological processes as induced by HIV-1 are worth considering since the results of our experiments are consistent with this assumption. HIV / automat / critic / protein

Pleiotrophin (PTN) is a polypeptide that belongs to a family of heparin-binding growth factor, which displays mitogenic activity for a wide variety of cells. Since PTN induces the proliferation of immune cells the mechanism of action was investigated. In the present study, we show for the first time that PTN induces the expression of inflammatory cytokines including TNF-alpha, IL-1beta and IL-6 in quiescent human peripheral blood mononuclear cells (PBMC). These results emphasize the importance of PTN in the regulation of inflammatory processes. Elucidation of the mechanisms by which a host factor such PTN regulates cytokines production will significantly advance our understanding of endothelium-immunity interactions.

BACKGROUND: Cell mediated immunity, including efficient CTL response, is required to prevent HIV-1 from cell-to-cell transmission. In previous investigations, we have shown that B1 peptide derived by Fourier transformation of HIV-1 primary structures and sharing no sequence homology with the parent proteins was able to generate antiserum which recognizes envelope and Tat proteins. Here we have investigated cellular immune response towards a novel non-homologous peptide, referred to as cA1 peptide. METHODOLOGY/PRINCIPAL FINDINGS: The 20 amino acid sequence of cA1 peptide was predicted using the notion of peptide hydropathic properties; the peptide is encoded by the complementary anti-sense DNA strand to the sense strand of previously described non-homologous A1 peptide. In this report we demonstrate that the cA1 peptide can be a target for major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes in HIV-1-infected or envelope-immunized individuals. The cA1 peptide is recognized in association with different MHC class I allotypes and could prime in vitro CTLs, derived from gp160-immunized individuals capable to recognize virus variants. CONCLUSIONS/SIGNIFICANCE: For the first time a theoretically designed immunogen involved in broad-based cell-immune memory activation is described. Our findings may thus contribute to the advance in vaccine research by describing a novel strategy to develop a synthetic AIDS vaccine.BACKGROUND: Cell mediated immunity, including efficient CTL response, is required to prevent HIV-1 from cell-to-cell transmission. In previous investigations, we have shown that B1 peptide derived by Fourier transformation of HIV-1 primary structures and sharing no sequence homology with the parent proteins was able to generate antiserum which recognizes envelope and Tat proteins. Here we have investigated cellular immune response towards a novel non-homologous peptide, referred to as cA1 peptide. METHODOLOGY/PRINCIPAL FINDINGS: The 20 amino acid sequence of cA1 peptide was predicted using the notion of peptide hydropathic properties; the peptide is encoded by the complementary anti-sense DNA strand to the sense strand of previously described non-homologous A1 peptide. In this report we demonstrate that the cA1 peptide can be a target for major histocompatibility complex (MHC) class I-restricted cytotoxic T lymphocytes in HIV-1-infected or envelope-immunized individuals. The cA1 peptide is recognized in association with different MHC class I allotypes and could prime in vitro CTLs, derived from gp160-immunized individuals capable to recognize virus variants. CONCLUSIONS/SIGNIFICANCE: For the first time a theoretically designed immunogen involved in broad-based cell-immune memory activation is described. Our findings may thus contribute to the advance in vaccine research by describing a novel strategy to develop a synthetic AIDS vaccine.

Cytotoxic T cells are the main antigen-specific effector cells of the cellular immune system and MHC class I restricted cytotoxic T-lymphocyte (CTL) responses in mice, acting against the HIV-1 envelope protein, are known to be predominantly directed against an amino acid sequence in the third hypervariable domain. We have investigated the epitope specificity of anti-HIV-1 CTL in healthy human volunteers inoculated with a recombinant vaccinia expressing the HIV-1 gp160 envelope gene. Their isolated lymphocytes were stimulated in vitro with autologous HIV-1 infected cells. Our results show that immunization with recombinant virus is able to generate virus-specific CTLs to the HIV-1 gp160 envelope protein and to a 15-residue synthetic peptide corresponding to a highly variable region of the envelope p18(IIIB). The CTL response was restricted by class I MHC molecules HLA-A2 and A3 that commonly occur in the human population.

Sarcolectin was originally described as an interferon antagonist, first detected in normal human muscles and in osteosarcomas. On the basis of a functional analysis of the protein, we postulated that the interferon antagonist is in fact an animal lectin . When cloned and expressed, the recombinant protein was found to be of 55 000 M . Fragments of sarcolectin molecules, when bound to albumin, react together in immune assays and create a 65 000-55 000 M complex and cannot be removed by heat denaturing or standard sodium dodecylsulphate gel-electrophoresis techniques. The biological functions of these sarcolectin proteins (from apparently various cellular origins) can be summarized as follows: (i) they promote agglutination of normal or malignant cells, because of their affinity for cell membrane bound sugars; and (ii) they inhibit the synthesis of the secondary proteins responsible for all the interferon-dependent biological functions that lead to the antiviral state. Consequently, the original virus-sensitive state is restored in the cells . Furthermore, in such sarcolectin-treated cells, refractoriness to a second interferon induction is diminished or abolished . They stimulate cellular DNA synthesis in all immune-competent cells, as well as in epithelial cells and fibroblasts in conformity with the known general properties of lectins. [1,2] r r [3]

The vast majority of in vitro experiments testing the cytotoxic T lymphocytes (CTL) activity in HIV infection has been performed with target cells consisting of autologous EBV-transformed B lymphoblastoid cell lines (B-LCLs) expressing Human immunodeficiency virus type I (HIV-1) proteins. However data concerning the lysis of primary CD4 + T lymphocytes expressing HIV-1 antigens by CTLs is still lacking. To study the CTL activity against such primary targets, we used a system involving PBMCs of an HIV + asymptomatic patient (PT) as effector cells and the CD4 + lymphocytes or B-LCLs of his healthy HLA-identical twin brother (HTW) as target cells. These syngeneic targets were either infected with recombinant vaccinia virus containing HIV-1 gag gene (gag-vac), or coated with HIV-1 gag peptides. We demonstrate in this study that PT CTLs (which were CD3 + , CD4 − , CD8 + , TCR α β + , TCR γ δ − , CD56 − ) specifically lysed both types of syngeneic target cells expressing gag-vac; however, CD4 + T cells expressing HIV gag proteins were lysed less efficiently than B-LCLs expressing the same HIV epitopes. On the other hand, no specific lysis was detected when the target cells were uninfected or infected by wild-type vaccinia virus.

Summary Peripheral blood mononuclear cells (PBMCs) are physiologically activated by interleukin (IL)-2. We found that oyster extract (JCOE) currently used as a functional nutrient enhanced in vitro the IL-2 dependent activation as measured by cell count, 3 H-thymidine uptake and up-regulation of a IL-2 receptor. In human immunodeficiency virus (HIV) seropositive individuals, this oyster extract-induced effect was marked in asymptomatic individuals with quasi-normal CD4 cell counts, but was weakly reflected in acquired immunodeficiency syndrome (AIDS) patients.

Summary Because T-cell responses are critical for defense against viral infections, the synthetic P18 peptide (RIQRGPGRAFVTIGK) and active component of gp160 protein has previously been shown to induce cytotoxic and helper T-lymphocyte responses. In order to further define the T-helper cells, responses which are known to play a role in enhancing the immunological response to foreign antigen, we studied the response of individuals immunized with HIV gp160 candidate vaccines. We investigated the proliferative cellular response of peripheral blood mononuclear cells (PBMC) derived from individuals immunized with gp160 antigens in three different protocols. We found a PBMC proliferative response to synthetic P18 peptide in healthy immunized individuals induced by gp160 antigen with or without vaccinia virus. There was correlation between the proliferative response to P18 peptide and other antigens such as HIV-like proteins and gp160 molecule. HLA-DR typing revealed the possible presentation of P18 peptide by several different class II molecules. Since these class II molecules occur frequently in the general population, P18 peptide appears to contain broadly reactive epitopes and thus is presented by mutiple HLA class II molecules. Due to its broad reactivity P18 peptide is one of the candidates for inclusion as a subunit vaccine against HIV-1.

Automat is a novel program which finds exhaustively all the oligopeptide segments shared by a given protein of any size with the proteins of a whole databank. It allows the user to collect statistics on the composition of the sequence studied in reference to the databank used. We present here the rationale and the algorithm underlying this powerful software. Besides its immediate interest for identifying efficiently similarities between proteins (or DNAs), biological applications of this software have already been described in the case of HIV-1 viral proteins, and Automat should prove useful also for studying more generally autoimmune diseases.

The effects of the HMG-Coenzyme A reductase inhibitor lovastatin on HIV-1 expression and sterol synthesis have been investigated in the human H9 lymphocytic cell line. To this purpose, sterol synthesis from 14C-acetate, cell multiplication and reverse transcriptase activity have been measured in parallel at various times after cell infection by HIV-1. It was found that nine days after viral loading, lovastatin inhibited both sterol synthesis and viral multiplication as assessed by the reverse transcriptase activity. Since HIV infection has been shown to induce alterations in membrane cholesterol content, suggesting that the virus cycle may be partially dependent upon cellular cholesterol, inhibitors of cholesterol synthesis could be an interesting way of research in order to slower HIV propagation.

We have previously unravelled the striking SLWDQ pentapeptide identity between HIV-1 env gp120 and the CD4 molecule. We show here that this pentapeptide is required for the functioning of the co-stimulatory MHC-CD4 signal in T4-cell activation since it suppresses antigen-induced T-cell proliferation. Moreover, concerning the MHC class II counterpart, the LNGQEETGVVSTN sequence which strongly inhibits T-cell immune activation is likely to be part of the functional site of the molecule. Interestingly the MHC/gp120 homology described by Young overlaps this MHC region. We further report that the gp120 SLWDQ peptide triggers an immune reaction which is both humoral (anti-SLWDQ antibodies) and cellular (CTLs against autologous targets carrying the pentapeptide) in HIVA infected individuals. Finally, anti-SLWDQ antibodies from patients sera purified by column chromatography strongly inhibit antigen-induced immune T-cell activation. This result led us to postulate that these antibodies found in high titers in HIVA infected individuals could contribute to set up the progressive systemic immune T-cell suppression characterizing AIDS.

HGP-30, the synthetic peptide analogue and active component in an HIV-1 (human immunodeficiency virus, type 1) p 17 core-based experimental vaccine, has previously been shown to induce cytotoxic and helper T-lymphocyte responses. In order to further define the T-helper cell responses which are known to play a role in enhancing the immunological response to foreign antigens, we studied the response of individuals infected with HIV to HGP-30 at various stages of disease progression. We have investigated the proliferative cellular response of peripheral blood mononuclear cells (PBMCs) derived from individuals infected with HIV-1 to HGP-30. We have found a PBMC proliferative response to HGP-30 in 40% of the healthy seroconverted patients, in 35% of the CDC stage III patients and in 18% of the CDC stage IV patients. There was no correlation between the proliferative response to HGP-30 and other antigens such as HIV-like proteins or tetanus toxoid not to CD4 cell count. HLA-DR typing revealed the possible presentation of HGP-30 by several different class II molecules. Since these class II molecules occur frequently in the general population, HGP-30 appears to contain broadly reactive epitopes and thus is not restricted as are many peptide vaccines. Due to its broad reactivity and extreme conservation in many HIV-1 strains. HGP-30 is one of the promising candidates for inclusion as a subunit vaccine against HIV-1.

In the first AIDS vaccine trial, immunizing preparations were based on HIV-1 Env protein (gp160). Immunogenic properties of gp160 which trigger both a humoral and cellular immune response have since justified its use in various vaccine programs, both past and present. Many reports however have underlined deleterious effects on the immune system — anti-HIV-1 enhanced antibodies, anti-CD4 autoantibodies, and inhibition of T cell activation by HIV-1 — particularly associated with the Env protein. The present study shows that gp160 presented in a biologically inactivated but immunogenic form, as used in our trial, could avoid these complications. Bio-hazards associated with gp0000 which indeed could be removed by appropriate treatment of the native protein, should be taken into consideration in AIDS vaccine programs. anti-AIDS vaccine / HIV-1 Env gp160 protein enhancing antibodies / anti-CD4 autoantibodies

The lysis by human and murine anti-HLA cytolytic T lymphocytes (CTL) of murine cells expressing class I HLA molecule after gene transfection has been studied using two different murine cells: LMTK- and P815-HTR-TK-. Weak but significant HLA-A11-specific lysis was found occasionally with human CTL on the HLA-A11+ L cells. On the contrary, P815-A11 or P815-A2 cells were lysed strongly and specifically by HLA-A11 or HLA-A2-specific human CTL. The T8+T4- phenotype of the effector cells was confirmed and the reaction was inhibited by anti-HLA class I monoclonal antibodies. Despite their higher sensitivity to human CTL, the P815-HLA+ cells did not express higher levels of HLA antigens than L cells, and the presence or the absence of human beta 2 microglobulin was irrelevant. Anti-human LFA-1 antibodies abrogated the lysis of P815-A11+ cells showing that the LFA-1 receptor which is apparently lacking on the L cell surface was on the contrary expressed on P815 cells. On the other hand, murine anti-HLA CTL have been prepared by immunizing mice against syngeneic HLA-A11+ L cells. They lysed very efficiently and specifically these cells, but appeared completely devoid of activity against human HLA-A11 target cells. This barrier was apparently due to the H-2 restriction of these H-2k anti-HLA murine CTL, as shown by their inability to lyse allogeneic H-2d cells expressing HLA-A11, and by the blocking of their activity by anti H-2k antibodies. By contrast, xenogeneic anti-HLA CTL obtained by immunizing murine lymphocytes against human cells lysed both human and murine HLA+ cells but they reacted with a monomorphic epitope of the HLA molecule in a nonrestricted way. These results show that human cells lyse very efficiently P815 murine cells expressing HLA class I antigens; the higher sensitivity of P815 cells compared to L cells is probably due to the presence of a LFA-1 receptor on these cells; a class I molecule of human origin can be seen as an H-2-restricted minor histocompatibility antigen in another species.

Recent findings support an indirect relationship between T cell depletion in HIV-1 infection and the rate of virus replication with implications for treatment strategies. We have initiated a new approach to recover immune function through the use of novel chemical agents. A cationic amphiphilic drug that binds to Ca(2+)-calmodulin at high concentrations, [10-[3-(4-methyl-1-piperazinyl)-propyl]-2- (trifluoromethyl)-(10)H-phenothiazine dihydrochloride] [denoted trifluroperazine dihydrochloride (Tfp); molecular weight 480.43] TFP was found at low concentrations (10(-6) to 10(-10) M) to help T cells from AIDS patients to restore proliferation in vitro. Here we show that the Tfp molecule can restore the cell survival of T lymphocytes from PBMCs derived from HIV-1-infected patients in vitro. Tfp enhances T cell proliferation and Th-cell responses by selectively inhibiting cell mortality and apoptosis. The restored antigen-specific response is associated with the synthesis of IL-2 and gamma-interferon. Even though this drug does not possess any detectable antiviral effect, it might be considered as a potential therapeutic agent in HIV-infected patients, to correct immune defects. Besides antiviral compounds, these data may facilitate immune reconstitution in patients with HIV infection and other immunosuppressive diseases.

CD14, CD68 and/or mouse F4/80 or human epidermal growth factor module-containing mucin-like receptor 1 (EMR1) are widely used as macrophage-specific markers. Since macrophages infiltrate several tissues during inflammatory processes, CD14, CD68 and EMR1-F4/80 have been employed to discriminate between tissue-containing macrophages, like adipose tissue (AT), and other cells. Using real-time PCR experiments, we show that isolated adipocytes from humans and mice AT express high levels of CD14 and CD68 mRNA, whereas EMR1-F4/80 is mainly present in the macrophage-containing stroma-vascular fraction. Furthermore, fibroblasts-like cells (adipoblasts), preadipocytes and adipocytes from the murine cell lines, 3T3-F442A and BFC-1, express CD14 and CD68 mRNA and protein as determined by fluorescence-activated cell sorter, but not F4/80 which, as expected, is strongly expressed in the macrophage cell line RAW264.7. These results reinforce the view that EMR1-F4/80 is the best macrophage marker to date and show that CD14 and CD68 are not macrophage-specific proteins.