The Effects of Curcuma longa L., Purple Sweet Potato, and Mixtures of the Two on Immunomodulation in C57BL/6J Mice Infected with LP-BM5 Murine Leukemia Retrovirus.

The immune response is stimulated to protect the body from external antigens and is controlled by several types of immune cells. In the present study, the immunomodulatory effects of Curcuma longa L., purple sweet potato, and mixtures of the two (CPM) were investigated in C57BL/6 mice infected with LP-BM5 murine leukemia virus (MuLV). Mice were divided into seven groups as follows: normal control, infected control (LP-BM5 MuLV infection), positive control (LP-BM5 MuLV infection+dietary supplement of red ginseng 300 mg/kg body weight), the original powder of C. longa L. (C; LP-BM5 MuLV infection+dietary supplement of C 189 mg/kg body weight), the original powder of purple sweet potato (P; LP-BM5 MuLV infection+dietary supplement of P 1811 mg/kg body weight), CPM Low (CPL; LP-BM5 MuLV infection+CPM 2 g/kg body weight), and CPM High (CPH; LP-BM5 MuLV infection+CPM 5 g/kg body weight). Dietary supplementation lasted for 12 weeks. Dietary supplementation of CPM inhibited LP-BM5 MuLV-induced lymphadenopathy and splenomegaly and inhibited reduction of messenger RNA (mRNA) expression of major histocompatibility complex (MHC) I and II. Moreover, CPM reduced the decrease in T- and B cell proliferation, reduced the population of CD4(+)/CD8(+) T cells, and remedied the unbalanced production of T helper-1 (Th1)/T helper-2 (Th2) cytokines in LP-BM5 MuLV-infected mice. In addition, CPM inhibited reduction of phagocytosis in peritoneal macrophages and decreased serum levels of immunoglobulin A (IgA), immunoglobulin E (IgE), and immunoglobulin G (IgG). These results suggest that CPM had a positive effect on immunomodulation in C57BL/6 mice induced by LP-BM5 leukemia retrovirus infection.

Activity of a novel combined antiretroviral therapy of gemcitabine and decitabine in a mouse model for HIV-1.

The emergence of drug resistance threatens to limit the use of current anti-HIV-1 drugs and highlights the need to expand the number of treatment options available for HIV-1-infected individuals. Our previous studies demonstrated that two clinically approved drugs, decitabine and gemcitabine, potently inhibited HIV-1 replication in cell culture through a mechanism that is distinct from the mechanisms for the drugs currently used to treat HIV-1 infection. We further demonstrated that gemcitabine inhibited replication of a related retrovirus, murine leukemia virus (MuLV), in vivo using the MuLV-based LP-BM5/murine AIDS (MAIDS) mouse model at doses that were not toxic. Since decitabine and gemcitabine inhibited MuLV and HIV-1 replication with similar potency in cell culture, the current study examined the efficacy and toxicity of the drug combination using the MAIDS model. The data demonstrate that the drug combination inhibited disease progression, as detected by histopathology, viral loads, and spleen weights, at doses lower than those that would be required if the drugs were used individually. The combination of decitabine and gemcitabine exerted antiviral activity at doses that were not toxic. These findings indicate that the combination of decitabine and gemcitabine shows potent antiretroviral activity at nontoxic doses and should be further investigated for clinical relevance.

Inhibition of premature death by isothiocyanates through immune restoration in LP-BM5 leukemia retrovirus-infected C57BL/6 mice.

The purpose of this study was to determine the effect of isothiocyanates (ITCs) in delaying the progression of the murine immunodeficiency virus to murine AIDS, resulting in increased life span. Furthermore, we investigated the role of ITCs in modulating immune dysfunction caused by LP-BM5 retrovirus infection. Among the tested ITCs, oral administration of sulforaphane (SUL), benzyl isothiocyante (BITC), and phenethyl isothiocyanate (PEITC) showed the inhibition of premature death caused by LP-BM5 retrovirus infection, while indolo[3,2-b] carbazole (ICZ) and indole-3-carbinol (I3C) did not delay the progress of the LP-BM5 retrovirus to murine AIDS. Inhibition of premature death by BITC, PEITC, and SUL could be explained by restoration of the immune system and down regulation of free radicals. Dysfunction of T and B cell mitogenesis caused by retrovirus infection in primary cultured splenocytes has been partially recovered with administration of BITC, PEITC, and SUL. There was a shift from imbalanced cytokine production (increased Th2 and decreased Th1 cell cytokine production) into balanced Th1/Th2 cell secretion of cytokines under administration of these ITCs during the development of murine AIDS. Hepatic vitamin E level was significantly restored by administration of these ITCs, in accordance with reduced hepatic lipid peroxidation levels. This study suggests that certain types of ITCs have beneficial effects in preventing premature death during progression to murine AIDS by restoration of immune dysfunction and removal of excessive free radicals, implying that selective usage of ITCs would be helpful in retarding the progression from HIV infection to AIDS.

Analysis of the ex vivo and in vivo antiretroviral activity of gemcitabine.

Replication of retroviral and host genomes requires ribonucleotide reductase to convert rNTPs to dNTPs, which are then used as substrates for DNA synthesis. Inhibition of ribonucleotide reductase by hydroxyurea (HU) has been previously used to treat cancers as well as HIV. However, the use of HU as an antiretroviral is limited by its associated toxicities such as myelosuppression and hepatotoxicity. In this study, we examined the ribonucleotide reductase inhibitor, gemcitabine, both in cell culture and in C57Bl/6 mice infected with LP-BM5 murine leukemia virus (LP-BM5 MuLV, a murine AIDS model). Gemcitabine decreased infectivity of MuLV in cell culture with an EC50 in the low nanomolar range with no detectable cytotoxicity. Similarly, gemcitabine significantly decreased disease progression in mice infected with LP-BM5. Specifically, gemcitabine treatment decreased spleen size, plasma IgM, and provirus levels compared to LP-BM5 MuLV infected, untreated mice. Gemcitabine efficacy was observed at doses as low as 1 mg/kg/day in the absence of toxicity. Higher doses of gemcitabine (3 mg/kg/day and higher) were associated with toxicity as determined by a loss in body mass. In summary, our findings demonstrate that gemcitabine has antiretroviral activity ex vivo and in vivo in the LP-BM5 MuLV model. These observations together with a recent ex vivo study with HIV-1, suggest that gemcitabine has broad antiretroviral activity and could be particularly useful in vivo when used in combination drug therapy.

Effect of macrophage depletion on viral DNA rebound following antiretroviral therapy in a murine model of AIDS (MAIDS).

In the attempt to eradicate HIV-1 infection, a strategy to eliminate macrophages, one of the most important cellular reservoirs in sustaining virus replication during HAART, could be of great benefit in the suppression of viral rebound. Aware of the ability of clodronate to cause macrophage depletion, the effect of the administration of clodronate encapsulated in erythrocytes on disease progression and on viral rebound was evaluated in a murine model of AIDS (MAIDS). One group of LP-BM5 retroviral complex-infected C57BL/6 mice received oral administrations of azidothymidine and dideoxyinosine daily for 12 weeks; two other groups received in addition, either clodronate-loaded erythrocytes or free clodronate at 7-10 day intervals. At the end of the treatment, the three groups maintained parameters characterizing disease progression similar to those of uninfected mice and showed a significantly lower level of BM5d DNA than infected mice in all organs and cells tested. To assess the viral rebound, some animals were left for an additional 4 month period without any treatment. After this time, the BM5d DNA content in blood leukocytes increased in all groups, but the group having received clodronate-loaded erythrocytes, in addition to transcriptase inhibitors, showed a significant delay in viral rebound.

Inhibition of murine AIDS by pro-glutathione (GSH) molecules.

Antioxidant molecules can be used both to replenish the depletion of reduced glutathione (GSH) occurring during HIV infection, and to inhibit HIV replication. The purpose of this work was to assess the efficacy of two pro-GSH molecules able to cross the cell membrane more easily than GSH. We used an experimental animal model consisting of C57BL/6 mice infected with the LP-BM5 viral complex; the treatments were based on the intramuscular administration of I-152, a pro-drug of N-acetylcysteine and S-acetyl-beta-mercaptoethylamine, and S-acetylglutathione, an acetylated GSH derivative. The results show that I-152, at a concentration of 10.7 times lower than GSH, caused a reduction in lymph node and spleen weights of about 55% when compared to infected animals and an inhibition of about 66% in spleen and lymph node virus content. S-acetylglutathione, at half the concentration of GSH, caused a reduction in lymph node weight of about 17% and in spleen and lymph node virus content of about 70% and 30%, respectively. These results show that the administration of pro-GSH molecules may favorably substitute for the use of GSH as such.

Combination of inhibitors of lymphocyte activation (hydroxyurea, trimidox, and didox) and reverse transcriptase (didanosine) suppresses development of murine retrovirus-induced lymphoproliferative disease.

The ribonucleotide reductase inhibitor hydroxyurea (HU) has demonstrated some benefit as a component of drug cocktails for the treatment of HIV-1 infection. However, HU is notoriously myelosuppressive and often administered only as salvage therapy to patients with late-stage disease, potentially exacerbating the bone marrow toxicity of HU. In this report we have compared the antiviral effects of HU and two novel RR inhibitors trimidox (3,4,5-trihydroxybenzamidoxime) and didox (3,4-dihydroxybenzohydroxamic acid) in combination with didanosine (2,3-didoxyinosine; ddI) in the LPBM5 MuLV retrovirus model (murine AIDS). We also evaluated the effects of these drug combinations on the hematopoietic tissues of LPBM5 MuLV-infected animals. The combination of RR inhibitors and ddI was extremely effective (DX>TX>HU) in inhibiting development of retrovirus-induced disease (splenomegaly, hypergammaglobulinemia, activated B-splenocytes and loss of splenic architecture). In addition, relative levels of proviral DNA were significantly lower in combination drug-treated animals compared to infected controls. Evaluation of femur cellularity, numbers of marrow-derived myeloid progenitor cells (CFU-GM and BFU-E) and peripheral blood indices revealed that TX and DX in combination with ddI were well-tolerated. However, treatment with HU and ddI induced moderate myelosuppression. These data demonstrate that RR inhibitors in combination with ddI provide significant protection against retroviral disease in murine AIDS. Moreover, the novel RR inhibitors TX and DX appear to be more effective and less myelosuppressive than HU when administered with ddI in this model.

Development of a real-time PCR assay using SYBR Green I for provirus load quantification in a murine model of AIDS.

A real-time PCR assay using SYBR Green I for quantification of provirus load in a murine model of AIDS (i.e., LP-BM5 infection) was developed and validated. In this method, data are normalized against the 18S rRNA gene. The method has a dynamic range of 8 logs and a sensitivity of one copy.

In vivo examination of hydroxyurea and the novel ribonucleotide reductase inhibitors trimidox and didox in combination with the reverse transcriptase inhibitor abacavir: suppression of retrovirus-induced immunodeficiency disease.

Inhibition of ribonucleotide reductase (RR) has gained attention as a potential strategy for HIV-1 therapy through the success of hydroxyurea (HU) to potentiate the activity of the nucleoside reverse transcriptase inhibitor (NRTI) didanosine (ddI) in clinical trials. However, the use of HU has been limited by its development of hematopoietic toxicity. In this study, the novel RR inhibitors didox (DX; 3,4-dihydroxybenzohydroxamic acid), and trimidox (TX; 3,4,5-trihydroxybenzamidoxime) were evaluated along with HU for anti-retroviral efficacy in LPBM5-induced retro-viral disease (MAIDS) both as monotherapeutic regimens and in combination with the guanine containing NRTI abacavir (ABC). Anti-retroviral drug efficacy was determined by measuring inhibition of splenomegaly, hypergammaglobulinemia, and splenic levels of proviral DNA. In this study, all RRIs tested showed the ability to improve the efficacy of ABC in the MAIDS model by reducing splenomegaly, hypergammaglobulinemia, and splenic proviral DNA levels.

Timed ablation of regulatory CD4+ T cells can prevent murine AIDS progression.

We describe successful immunotherapy of murine AIDS (MAIDS) in C57BL/6J mice based on the elimination of replicating CD4(+) regulator T cells. We demonstrate that a single injection of the antimitotic drug vinblastine (Vb) given 14 days postinfection (p.i.) with LP-BM5 can prevent MAIDS progression. Treatment with anti-CD4 mAb at 14 days p.i. is similarly able to prevent MAIDS. Treatment at other time points with Vb or anti-CD4 mAb is ineffective. The effect is based on ablation of a replicating dominantly suppressive CD4(+) T cell population, as indicated by adoptive transfer and in vivo depletion experiments using mAbs against CD4 as well as combinations of mAbs against the known regulatory cell surface markers CD25, GITR, and CTLA-4. Cell surface marker analysis shows a population of CD4(+)CD25(+) cells arising shortly before day 14 p.i. Cytokine analyses show a peak in IL-10 production from day 12 to day 16 p.i. MAIDS-infected mice also have CD4(+) T cells with significantly higher expression levels of CD38 and particularly CD69, which have been demonstrated to be regulator T cell markers in the Friend retroviral model. The immunotherapy appears to prevent disease progression, although no protection against reinfection with LP-BM5 is generated. These data define a new therapy for murine retroviral infection, which has potential for use in other diseases where T regulator cell-mediated immunosuppression plays a role in the disease process.

Effect of bovine lactoferrin on a transmissible AIDS-like disease in mice.

The effect of bovine lactoferrin (bLF) was examined on an AIDS-like disease (ALD) in mice. Induction of disease was achieved by inoculation with infected cell-free plasma from diseased mice to uninfected ones. The effect of treatment with bLF was investigated when administered simultaneously with the virus, 20 days prior to infection, or 20 days after infection. Animals underwent clinical surveillance and enumeration of white blood cells (WBC) and lymphocytes, as well as fluorescent staining of CD4 and CD8 bearing cells. Simultaneous administration of bLF and virus did not affect the pattern of ALD progress along the course of the experiment. Pretreatment with bLF prior to virus inoculation abolished on day 21 the detrimental effect of viral infection that lasted for two months. An opposite outcome was observed when bLF was administered 20 days after the virus. It seems that bLF had played a preventive role for a restricted period of time. However, an adverse response was elicited when bLF was administered 20 days after viral infection.

Repeated cycles of alternate administration of fludarabine and Zidovudine plus Didanosine inhibits murine AIDS and reduces proviral DNA content in lymph nodes to undetectable levels.

The results of the combined use of Fludarabine, an anticancer agent that may be able to target latently infected cells, and conventional antiretroviral therapy (AZT+DDI) in a murine model of AIDS, i.e., LP-BM5 infection, are reported. Eighty percent of infected mice, treated with four cycles of alternate administration of Fludarabine and AZT+DDI, showed undetectable levels of proviral DNA in lymph nodes. After 8 weeks of treatment interruption, the infected/treated animals, although still alive at a time when all untreated animals had succumbed to the infection, showed disease progression and reappearance of proviral DNA in lymph nodes. The retrospective analysis of proviral DNA content in spleen and bone marrow at the end of the fourth cycle of treatment revealed a low but detectable amount of BM5d proviral DNA. We thus concluded that the spleen and bone marrow may be less sensitive to lympholitic drugs and therefore act as viral reservoirs in LP-BM5 infection. This study suggests that optimized protocols of alternate administration of cytolytic and antiretroviral drugs may represent a useful strategy to eradicate retroviral infections.

Macrophage protection by addition of glutathione (GSH)-loaded erythrocytes to AZT and DDI in a murine AIDS model.

Monocyte-macrophages play a central role in HIV-1 infection because they are among the first cells to be infected and because later they are important reservoirs for the virus. Thus, newly designed therapies should take into account the protection of this cell compartment. Herein, we report the results obtained in a murine AIDS model, by the addition to AZT+DDI of a system (GSH-loaded erythrocytes) able to protect macrophages against HIV-1 infection. Five groups of LP-BM5-infected mice were treated as follows: one group was treated by AZT, one group was treated by DDI, one group was treated by the combination of both, another by GSH-loaded erythrocytes, and finally, one by the combination of all three. After 10 weeks of infection the parameters of the disease were studied and the proviral DNA content in different organs and in macrophages of bone marrow and of the peritoneal cavity was quantified. The results obtained show that mice treated with AZT+DDI+GSH-loaded erythrocytes showed proviral DNA content in the brain and in macrophages of bone marrow that was significantly lower than in mice treated with AZT+DDI. This study may help developing strategies aimed at blocking HIV-1 replication in its reservoirs in the body.

Inhibition of murine AIDS by a heterodinucleotide of azidothymidine and 9-(R)-2-(phosphonomethoxypropyl)adenine.

Tenofovir [9-(R)-2-(phosphonomethoxypropyl)adenine (PMPA)] and zidovudine [azidothymidine (AZT)] are potent anti-HIV agents that have shown a strong synergy in in vitro studies. In this paper we have investigated both the potentiality of this synergy in vivo and the possibility to administer AZT and PMPA simultaneously as a single drug AZTpPMPA. The pharmacokinetic studies reported here have shown that AZTpPMPA administered intraperitoneally in mice performs as a prodrug, providing a slow delivery of AZT and PMPA in circulation. C57BL/6 mice infected with the retroviral complex LP-BM5 were used to evaluate the efficacy of AZTpPMPA in inhibiting disease progression. Furthermore, the effectiveness of the heterodinucleotide was compared with that of AZT and PMPA, administered as single drugs, or as a combination (AZT plus PMPA). The results obtained showed that AZTpPMPA is able to reduce lymphoadenopathy (88%), splenomegaly (64%), lymph node BM5 proviral DNA content (49%) and hypergammaglobulinaemia (40%). However, upon AZT plus PMPA administration, similar (splenomegaly and lymphoadenopathy reduction) or better results (64% hypergammaglobulinaemia reduction and 75% lymph node BM5 proviral DNA content inhibition) were obtained. Furthermore, these results overlapped those obtained upon PMPA administration. Thus, no synergy between PMPA and AZT was observed in murine AIDS and administration of AZT does not improve the antiviral results obtained by PMPA administration.

Suppression of retrovirus-induced immunodeficiency disease (murine AIDS) by trimidox and didox: novel ribonucleotide reductase inhibitors with less bone marrow toxicity than hydroxyurea.

Recently, the use of the ribonucleotide reductase (RR) inhibitor hydroxyurea (HU) in combination with nucleoside analogs has gained attention as a potential strategy for anti-HIV-1 therapy. However, appeal for the long-term use of HU in HIV-1 infection may be limited by its propensity to induce hematopoietic toxicity. We report a comparison of the efficacy and bone marrow toxicity of HU (400 and 200 mg/kg/day) with the novel RR inhibitors and free radical-scavenging compounds didox (DX; 3,4-dihydroxybenzohydroxamic acid; 350 mg/kg/day) and trimidox (TX; 3,4,5-trihydroxybenzamidoxime; 175 mg/kg/day) in the murine AIDS (LPBM5 MuLV) model of retrovirus infection. Infected mice received daily drug treatment for 8 weeks. Efficacy was determined by measuring drug effects on retroviral-induced disease progression (i.e. development of splenomegaly and hypergammaglobulinemia) and by evaluating splenic levels of proviral DNA. Bone marrow toxicity was evaluated by measuring peripheral blood indices (WBC, hematocrit and reticulocyte counts), femoral cellularity and by determining the numbers of hematopoietic progenitor cells (CFU-GM, BFU-E) per femur and spleen. Compared to infected controls receiving no drug treatment, disease progression was significantly suppressed by TX, DX and HU. However, HU was associated with mortality and induced significant hematopoietic toxicity in a time- and dose-dependent manner. Conversely, TX and DX effectively inhibited retrovirus-induced disease but did not induce hematopoietic toxicity. These results suggest that due to their reduced hematopoietic toxicity and ability to inhibit disease progression in murine AIDS, TX and DX may offer effective alternatives to HU therapy in HIV-1 infection.

Effects of Z-100, a Mycobacterium-tuberculosis-derived arabinomannan, on the LP-BM5 murine leukemia virus infection in mice.

OBJECTIVE: To investigate the effects of Z-100, an arabinomannan extracted from Mycobacterium tuberculosis, on the LP-BM5 murine leukemia virus (LP-BM5 MuLV) infection in mice. METHODS: C57BL/6 mice infected intraperitoneally with 4.5 x 10(2) PFU/mouse of LP-BM5 MuLV (MAIDS mice) were treated intraperitoneally with a 10-mg/kg dose of Z-100 every other day beginning 1 day after the viral infection. MAIDS mice treated with Z-100 were compared with control mice (MAIDS mice treated with saline) for their survival and splenomegaly after LP-BM5 infection. Cytokine-producing profiles of splenic T cells from these two groups of mice were also compared. RESULTS: When MAIDS mice treated with Z-100 were compared with those of control mice, a decrease in splenomegaly and lymphadenopathy was observed. Splenomegaly was markedly enhanced in MAIDS mice treated intraperitoneally with IL-4 or IL-10. When MAIDS mice were treated with Z-100, their survival rates were significantly increased compared to those of controls. Splenic T cells from control mice produced type-2 cytokines (IL-4 and IL-10). However, a decreased production of type-2 cytokines by splenic T cells from MAIDS mice treated with Z-100 was demonstrated. CONCLUSION: Z-100 could decrease the severity of the LP-BM5 MuLV infection through the regulation of MAIDS-associated type-2 T-cell responses.

T-cell receptor-derived peptides in immunoregulation and therapy of retrovirally induced immunosuppression.

Retrovirally infected humans and mice showed progressive acquired immunodeficiency accompanied by the production of elevated levels of autoantibodies directed against T-cell receptor variable-domain epitopes. Epitope mapping analyses indicated that a major determinant recognized was defined by a 16-mer peptide containing the entire CDR1 segment and part of the FR2 region of human Vbeta8, and that both species showed reactivity to the same sequence. Either prophylactic or therapeutic administration of this peptide to retrovirus-infected C57/BL/6 mice normalized the balance of T(H)1- and T(H)2-type helper activity and restored the resistance to infection by the opportunistic parasite Cryptosporidium. Administration of the peptide did not generate significantly increased levels of autoantibody, but had a profound effect on T-cell activity as well as other aspects of inflammation, including NK-cell activity. A 16-mer derived from the Jbeta sequence showed similar functional effects on T cells from retrovirus-infected mice. Direct binding of the VbetaCDR1 peptide to recombinant TCR Valpha/Vbeta constructs, as well as to IgM natural autoantibodies, suggests that the cell surface receptor for the peptide is the alpha/beta TCR on T cells and surface IgM in B cells. The Vbeta CDR1 peptide stimulated division of murine splenocytes in vitro, stimulated the production of the T(H)1 cytokine IL-2, and synergized with the T-cell mitogen concanavalin A in proliferation and IL-2 production. These studies indicate that administration of peptides derived from T-cell receptor variable domains to animals immunosuppressed as a result of retroviral infection has a profound immunomodulatory effect enhancing overall T-cell functional capacity, particularly with respect to the cytokine production characteristic of T(H)1-type cells. Our studies are interpreted in the context of other recent investigations of immunomodulatory peptides.

Immunomodulatory effect of gold sodium thiomalate on murine acquired immunodeficiency syndrome.

Induction of IL-2 production and increased expression of CD25 were observed in C57BL/10 mice after weekly treatment with gold sodium thiomalate (GST). LP-BM5 murine leukemia virus (MuLV) infected mice treated with GST survived longer, had less cervical lymph node swelling, lower spleen weight, and fewer abnormalities in the expression of the cell surface markers, CD4, CD8a and CD45R/B220 on spleen cells than those that were not treated with GST. Thus, GST treatment may be beneficial through a decrease in disease progression via IL-2 induction in MuLV infected mice. This may have application in human immunodeficiency virus-infected individuals.

Characterization of the CD154-positive and CD40-positive cellular subsets required for pathogenesis in retrovirus-induced murine immunodeficiency.

Genetically susceptible C57BL/6 (B6) mice that are infected with the LP-BM5 isolate of murine retroviruses develop profound splenomegaly, lymphadenopathy, hypergammaglobulinemia, terminal B-cell lymphomas, and an immunodeficiency state bearing many similarities to the pathologies seen in AIDS. Because of these similarities, this syndrome has been called murine AIDS (MAIDS). We have previously shown that CD154 (CD40 ligand)-CD40 molecular interactions are required both for the initiation and progression of MAIDS. Thus, in vivo anti-CD154 monoclonal antibody (MAb) treatment inhibited MAIDS symptoms in LP-BM5-infected wild-type mice when either a short course of anti-CD154 MAb treatment was started on the day of infection or a course was initiated 3 to 4 weeks after LP-BM5 administration, after disease was established. Here, we further characterize this required CD154-CD40 interaction by a series of adoptive transfer experiments designed to elucidate which cellular subsets must express CD154 or CD40 for LP-BM5 to induce MAIDS. Specifically with regard to CD154 expression, MAIDS-insusceptible B6 nude mice reconstituted with highly purified CD4+ T cells from wild-type, but not from CD154 knockout, B6 donors displayed clear MAIDS after LP-BM5 infection. In contrast, nude B6 recipients that received CD8+ T cells from wild-type B6 donors did not develop MAIDS after LP-BM5 infection. B6 CD40 knockout mice, which are also relatively resistant to LP-BM5-induced MAIDS, became susceptible to LP-BM5-induced disease after reconstitution with highly purified wild-type B cells but not after receiving purified wild-type dendritic cells (DC) or a combined CD40+ population composed of DC and macrophages obtained from B6 SCID mouse donors. Based on these and other experiments, we thus conclude that the cellular basis for the requirement for CD154-CD40 interactions for MAIDS induction and progression can be accounted for by CD154 expression on CD4+ T cells and CD40 expression on B cells.

New drug combinations for the treatment of murine AIDS and macrophage protection.

The failure of highly active antiretroviral therapies (HAART) is mainly due to the existence of latent infected reservoirs, such as macrophages and resting CD4+ T cells. In this paper, we report the results that we obtained in a murine model of AIDS by alternating the administration of the lympholitic drug 2-Fluoro-ara-AMP (Fludarabine) to eliminate the infected cells, with that of Azidothymidine (AZT) plus reduced glutathione (GSH) encapsulated in erythrocytes, to protect lymphocytes and macrophages not yet infected, respectively. Two groups of infected mice were treated as follows: one group was treated by alternating the administration of Fludarabine and AZT (treatment A), while the other group received the same treatment plus GSH-loaded erythrocytes given with AZT (treatment A + L-RBC). Fludarabine was administered intraperitoneally, AZT in the drinking water and GSH was encapsulated in erythrocytes by a procedure of hypotonic dialysis and isotonic resealing. The results obtained show that GSH-loaded erythrocytes provide additive effects in all the parameters examined. Alternation of a lympholitic drug and antiretroviral drug is effective in reducing the progression of murine AIDS. Addition of a system to protect macrophages provides additive effects in almost all the parameters considered, confirming that combination therapies aimed at protecting different infectable cell compartments are better than treatments protecting mainly lymphocytes.