Since the introduction of antiretroviral therapy(ART),the lifespan and quality of life of patients infected with HIV have been significantly improved.But treatment efficacy was compromised eventually by the development of resistance to antiretroviral drugs,and more new anti-HIV drugs with lower toxicity and higher activity were needed.Based on the experience and lessons learned from the treatment in the developed countries,US FDA suggested that more pharmacodynamical researches should be considered ahead of the clinical trials.To facilitate the anti-HIV drug research and development,we reviewed a few specialized issues that should be focused on drug evaluations in vitro,including: 1)Mechanism of action studies,demonstrating the candidate drug's efficacy to specifically inhibit viral replication or a virus-specific function and confirm the drug target.2)Drug resistance studies,selecting the drug-resistant variants in vitro and determining the activities inhibiting HIV isolates resistant to approved antiretroviral drugs of the same class.3)Antiviral activity in vitro in the presence of serum proteins,ascertaining whether an investigational product is significantly bound by serum proteins.4)Combination activity analysis,evaluating in vitro antiviral activity of an investigational product in two-drug combinations with other drugs approved.

JB25 and JB26 are new HIV-1 nonnucleoside reverse transcriptase inhibitors, and show potent anti-HIV activities. Sequential passage experiments with wild-type virus were performed to select and identify mutations induced by these two compounds in vitro. For the initial passage, compounds were present at approximately 2-fold IC50 in MT-2 cells. When cytopathic effect (CPE) was observed in more than 75% of the cells, the culture supernatants were collected. For the subsequent passages, fresh MT-2 cells were infected with 1 mL supernatants from the previous passage (regardless of the virus titer) and cultured in the presence of the compounds at concentrations that were increased 2-fold compared with that in the previous passage. This procedure was repeated with increasing concentrations for 12 passages. JB25 had amino acid substitution L100I (TTA-->ATA) at passage 6, and then changed into 100 M (ATA-->ATG) at passage 12, which was rare mutation form and had not been reported. At the same time, Y188C (TAT-->TGT) mutation appeared at passage 10. For JB26, there was a L100I (TTA-->ATA) mutation at passage 10. In a word, JB25 and JB26 showed a low genetic barrier to the development of resistance, and the resistance to JB26 developed slower than JB25. The mutations selected by JB25 and JB26 were mainly associated with codons 188 and 100 of HIV-1 reverse transcriptase.

Human Immunodeficiency Virus Type 1 exists in vivo as quasispecies, and one of the genome's characteristics is its diversity. During the antiretroviral therapy, drug resistance is the main obstacle to effective viral prevention. Understanding the molecular evolution process is fundamental to analyze the mechanism of drug resistance and develop a strategy to minimize resistance. Objective: The molecular evolution of drug resistance of one patient who had received reverse transcriptase inhibitors for a long time and had treatment which replaced Nevirapine with Indinavir was analyzed, with the aim of observing the drug resistance evolution pathway. Methods: The patient, XLF, was followed-up for six successive times. The viral populations were amplified and sequenced by single-genome amplification. All the sequences were submitted to the Stanford HIV Drug Resistance Database for the analysis of genotypic drug resistance. Results: 149 entire protease and 171 entire reverse transcriptase sequences were obtained from these samples, and all sequences were identified as subtype B. Before the patient received Indinavir, the viral population only had some polymorphisms in the protease sequences. After the patient began Indinavir treatment, the variants carrying polymorphisms declined while variants carrying the secondary mutation G73S gained the advantage. As therapy was prolonged, G73S was combined with M46I/L90M to form a resistance pattern M46I/G73S/L90M, which then became the dominant population. 97.9% of variants had the M46I/G73S/L90M pattern at XLF6. During the emergence of protease inhibitors resistance, reverse transcriptase inhibitors resistance maintained high levels. Conclusion: Indinavir- resistance evolution was observed by single-genome amplification. During the course of changing the regimen to incorporate Indinavir, the G73S mutation occurred and was combined with M46I/L90M.

Objective To characterize 5 gpl20 sequences from mainly circulating clades in China and expression of their gp120 glycoproteins. Methods gp120 genes were amplified from the PBMCs of 5 HIV-1 infected individuals in different provinces using nest PCR and their DNA sequences were determined. Sequence characteristics were analyzed and gp120 genes were sub-cloned into the mammalian expression vec-tor to produce gp120 glycoproteins. Results Sequence characteristics indicated these sequences belong to the clade Thai-B, CRF_BC and CRF_AE, respectively. There were some conservative N-linked glycosyla-tion sites and primary Furin protease cleavage motifs in the same positions within gp120 amino acid se-quences although these gp120 sequences were categorized into different clades. In comparison with referen-tial strains, amino acids deletions were found in the V1, V2, V4, V5 regions except for the V3 loop; above all, V3 tip motifs of Thai-B exhibited the more polymorphic forms than those of CRF_BC and CRF_AE. These 5 gp120 sequences were cloned into the eukaryotic expression vector and gpl20 glycoproteins were produced successfully. Conclusion Hyper-variable nature of Env should be considered while designing HIV-1 vaccine or test reagent, and gpl20 expression in vitro is helpful to further research on the Env patho-genesis and vaccine development against the mainly circulating HIV-1 isolates in China.

ObjectiveTo evaluate the sensitivity and accuracy of an in-house detecting method of HIV-1 genotypic drug resistance system. MethodsTotally 130 serum specimens from Henan and Guangxi province were collected from April 2004 to October 2008 and tested in the Military HIV Testing Center of China. ViroSeqTM v2.0 (Abbott, Switzerland), a US FDA approved HIV genotypic drug resistance detecting system was utilized as the reference method. All the specimens were detected by the novel in-house method and the reference method to validate the difference in amplifying efficiency, drug resistance mutation detection and drug resistance report. ResultsConcerning the 14 850 known drug resistance mutation sites,14 752 (99. 3％ ) mutations can be detected by both of the two methods. Rates of concordance of detection in the regions of protease inhibitors-, reverse transcriptase inhibitors- and both two classes inhibitors-resistance were99.7％ ( Kappa =0. 909 9 , P ＜0. 01 ) , 99. 0％ (Kappa=0.952 1, P＜0. 01) and99.3％ (Kappa=0. 948 8, P ＜ 0. 01 ) respectively. Drug resistance reports from these two systems showed similar results (Kappa = 0. 637 4, P ＜ 0. 01 ). The in-house detecting system identified 34 novel mutations besides the ViroSeqTM drug resistance mutation database ( ViroSeqTM software v2. 7). Two mutations, V179F and K238T,had significant effect on HIV drug resistance. ConclusionsThe in-house genotyping system is an accurate,cost-effective method and has a high concordance with commercial ViroSeqTM genotyping system. Database from the in-house assay was superior to this of the ViroSeqTM assay.

Objective To determine whether Morphine has the ability to enhance HIV-1 replication in MT2 and Macrophage in vitro and assess the influence of Naloxone on Morphine2s effect.Methods MT2 cells were randomly assigned into 4 groups: (1) Morphine treatment for MT2 group, (2) Morphine+Naloxone co-treatment for MT2 group, (3) Naloxone treatment for MT2 group and (4) MT2 Control;Macrophages were also randomly assigned into 4 groups: (5) Morphine treatment for Macrophage group, (6) Morphine+Naloxone co-treatment for Macrophage group, (7) Naloxone treatment for Macrophage group and (8) Macrophage Control. Group (2), (3), (6) and (7) were pre-treated with 10-8 mol/L Naloxone for 0.5 h, and then group (1) and (2) were treated with 10-12, 10-10 and 10-8 mol/L Morphine for 24 h;group (5) and (6) were disposed of 10-10 mol/L Morphine for 24 h.All 8 groups were added in HIV-1 viral strain with 50% tissue culture infective dose(TCID50).P24 antigen in MT2 cells culture supernatant at day 3, 4, 5 and 6, and in Macrophages culture supernatant at day 4, 6, 8, 10 and 12 after infection were determined with ELISA.Student2s t-test and ANOVA were used to compare the differential expression in different groups, and repeated measures ANOVA was used to compare the increasing or decreasing expression of p24 antigen in morphine treatment groups than that in the control group at different time points.Results On the 3rd day of infection with HIV-1 in MT2 cells, the expression of p24 antigen in 10-12, 10-10 and 10-8mol/L dose of group (1) were (4.44?.30), (5.59?.25) and (4.60?.24) ng/ml respectively, compared to control[(1.93?.05) ng/ml, t= 14.15, 24.74 and 19.14, all P<0.01].On the 4th day, 10-12, 10-10 and 10-8mol/L dose of group (1) resulted in a significant increase of p24 antigen expression [(24.30?.66), (31.73?.17) and (26.02?.37) ng/ml]in culture supernatants compared to control[(8.03?.09) ng/ml, t=10.59, 34.92 and 81.2, all P<0.01].On the 5th day, the expression of p24 antigen in 10-12, 10-10 and 10-8 mol/L dose of group (1) were (56.30?.26), (81.77?.49) and (63.66?.57) ng/ml respectively, compared to control [(15.30?.91) ng/ml, t= 45.83, 43.51 and 30.07, all P<0.01].On the 6th day, the expression of p24 antigen in 10-12, 10-10 and 10-8 mol/L dose of group (1) were (150.70?.97), (243.09?.93) and (173.72?.73) ng/ml respectively, compared to control [(41.01?.84) ng/ml, t= 21.09, 39.02 and 29.55, all P<0.01].The enhanced multiple of p24 antigen expression in three doses of morphine treatment group compared to control increased with HIV-1 infected MT2 cells time, trend analysis of repeated measurements showed statistically significant time effect (F=842.18, P<0.01). On the 4th day of infection with HIV-1 in Macrophage cells, the expression of p24 antigen in 10-12, 10-10 and 10-8 mol/L dose of group (5) were (0.68?.15), (0.87?.41) and (0.75?.09) ng/ml respectively, compared to control [(0.60?.01) ng/ml, t= 7.27, 11.06 and 3.02, all P<0.05]. On the 6th day, 10-12, 10-10 and 10-8 mol/L dose of group (5) resulted in a significant increase of p24 antigen expression[(1.64?.57) , (2.07?.12 ) and (1.75?.17) ng/ml]in culture supernatants compared to control [(1.16?.07) ng/ml, t=8.93, 11.3 and 5.45, all P<0.01].On the 8th day, the expression of p24 antigen in 10-12, 10-10 and 10-8 mol/L dose of group (5) were (6.31?.17), (8.81?.34) and (7.19?.11) ng/ml respectively, compared to control [(3.84?.45) ng/ml, t=8.83, 15.11 and 12.42, all P<0.01]. On the 10th day, the expression of p24 antigen in 10-12, 10-10 and 10-8 mol/L dose of Morphine treated group were (32.30?7.55), (50.74?7.55) and (39.74?.56) ng/ml respectively, compared to control [(17.55?.86) ng/ml, t= 13.65, 17.84 and 36.69, all P<0.01].The enhanced multiple of p24 antigen expression in three doses of group (5) compared to control increased with HIV-1 infected Macrophage cells time, trend analysis of repeated measurements showed statistically significant time effect (F=135.58, P<0.01).Conclusions Morphine has the ability to enhance HIV-1 replication in MT2 cell and Macrophage. This Morphine-mediated increase of p24 antigen expression can be blocked by Naloxone.

Objective To develop and evaluate the allele-specific real-time PCR(ASPCR) assay for the detection of minor HIV-1 variants. Methods We developed and evaluated the ASPCR assay, using the K103N mutation site as a model system. We constructed plasmids as standards and designed specific and non-specific primers to discriminate the wild-type and mutant plasmids in the real-time PCR using SYBR green as fluorescence reporter. And then we evaluated the sensitivity, accuracy, reproducibility of ASPCR assay and detected the control samples. Results The specific primer can discriminate the wild-type and mutant plasmids including resistant mutation successfully. The sensitivity of ASPCR assay can achieve less than 0.01% and the accuracy of this method is down to 0.1%. The Intra-assay coefficient of variation is less than 0.7 and the Inter-assay coefficient of variation is less than 1.6. Conclusion ASPCR is a sensitive, accurate and rapid method to detect the minor HIV-1 variants which have resistant mutations and it can be used widely in HIV research. ASPCR also can provide earlier and more resistant information to the clinical therapy.

Neutralizing antibodies are considered to be an important protective parameter used in HIV-l vaccine evaluation.However,the exact role that neutralizing antibodies plays in controlling the disease progression of HIV-1 infected peoples is still undetermined.In this paper,we compared the protective function of the neutralizing antibody response in the plasma from LTNP and TP against clade B and clade C pseudoviruses.No difference in the neutralizing activities between the plasma from LTNP and TP was found,which was consistent with the most recent reports.In addition,no correlations between the titer or breadth and CD4+ or viral load in HIV-1 infected individuals were found.The protective roles played by neutralizing antibodies in controlling disease progression of HIV-1 infected people need to be considered in a new viewpoint.

Objective To evaluate the antiretroviral therapy(ART),analyze the prevalence of resistance in rural areas,Henan,and explore the presence of minor resistant variants in pre-ART.Methods One hundred and forty-nine AIDS patients initiating ART were recruited and investigated at intervals of 6 months. Method of In-house developed by our laboratory for genotypjc resistance test was to analyze the occurrence of resistance among the failure of ART,and the allele-specific real.time PCR(ASPCR)was used to detect the minor resistant variants at the baseline samples once the resistance occurred.Results Vimlload significantly decreased among the patients who received ART(t=275,P=0.0001),but the absolute counts of CD4+T lymphocytes had no significant change(t=1.765 168,P=0.0852).Rate of resistance among the patients of treatment failure was 4.88%.The result of ASPCR in the survey of baseline showed that the minor resistant variants of M184V were detected in 7 patients and mutation K103N presented in 5 patients.Conclusion The primary drug-resistant straias in the untreated patients were found in Henan,and they might develop the dominant resistance strains and bring about the failure of ART.

Objective To isolate stable passage primary HIV-1 drug resistant strains and observe replication dynamics of the drug resistant isolates and evolvement tendency of the drug resistant mutations in vitro.Methods Peripheral blood mononuclear cells(PBMCs)from 15 AIDS patients receiving highly active antiretroviral therapy(HAART)were collected,and the primary HIV-1 stains were separated utilizing co-cultivated with PBMCs from normal people.HIV-1 pol genes from those strains were obtained by RT-PCR and sequenced.The drug resistant mutations were analyzed in the Stanford HIV Drug Resistance Database.Results Eight strong positive strains were isolated from 15 AIDS patients with viral loads higher than 1000 copies/ml,and two of them were drug resistant.Drug resistant mutations of the two strains were respectively K103N/K238T and M184V/K103N/Y181C/H221Y which show high-level resistance to NVP and 3TC/NVP,respectively.K103N,M184V,Y181C and H221Y exist stably in the environment without drug pressure,however,RT K238T reverted to K238.Conclusion Two drug resistant strains were successfully isolated in vitro without drug pressure.Strains with K103N shows superior fitness and can exist steadily.Strains with M184V and K103N/Y181C/H221Y can also replicate stably in vitro without drug pressure.NNRTI mutation K238T reproduces astatically,which suggests that RT 238 codon might revert gradually to wild genotype.