title: Characterization of two HIV-1 infectors during initial antiretroviral treatment, and the emergence of phenotypic resistance in reverse transcriptase-associated mutation patterns.
abstract: BACKGROUND
  Highly active antiretroviral therapy (HAART) is recommended to control the infection of HIV-1. HIV-1 drug resistance becomes an obstacle to HAART due to the accumulation of specific mutations in the RT coding region. The development of resistance mutations may be more complex than previously thought.
  
  
  METHODS
  We followed two HIV-1 infectors from a HIV-1 drug resistance surveillance cohort in Henan province and evaluated CD4+ T-cell number and viral load thereafter at ten time-periods and characterized their reverse transcriptase-associated mutation patterns at each time point. Then we constructed the recombinant virus strains with these mutation patterns to mimick the viruses and test the phenotypic resistance caused by the mutation patterns on TZM-b1 cells.
  
  
  RESULTS
  CD4+ T-cell number initially increased and then decreased rapidly, while viral load decreased and then dropped sharply during initial antiretroviral treatment. The number of mutations and the combination patterns of mutations increased over time. According to the phenotypic resistance performed by recombinant virus strains, VirusT215Y/V179E/Y181C/H221Y exhibited high levels of resistance to EFV (5.57-fold), and T215Y/V179E-containing virus increased 20.20-fold in AZT resistance (p < 0.01). VirusT215Y/V179E/Y181C increased markedly in EFV resistance (p < 0.01). The IC50 for VirusT215Y/V179E/H221Y was similar to that for VirusT215Y/V179E/Y181C. VirusT215Y/K103N/Y181C/H221Y induced a dramatic IC50 increase of all the four agents (Efavirenz EFV, Zidovudine AZT, Lamivudine 3TC, and Stavudine d4T) (p < 0.01). As for VirusT215Y/K103N/Y181C, only the IC50 of EFV was significantly increased. T215Y/K103N resulted in a 26.36-fold increase in EFV (p < 0.01). T215Y/K103N/H221Y significantly increased the resistance to AZT and 3TC. The IC50 of EFV with T215Y/V179E was lower than with T215Y/K103N (F = 93.10, P < 0.0001). With T215Y/V179E, Y181C significantly increase in EFV resistance, while the interaction between 181 and 221 in EFV was not statistically significant (F = 1.20, P = 0.3052). With T215Y/K103N, neither H221Y nor Y181C showed a significant increase in EFV resistance, but the interaction between 181 and 221 was statistically significant (F = 38.12, P = 0.0003).
  
  
  CONCLUSIONS
  Data in this study suggests that pathways of viral evolution toward drug resistance appear to proceed through distinct steps and at different rates. Phenotypic resistance using recombinant virus strains with different combination of mutation patterns reveals that interactions among mutations may provide information on the impact of these mutations on drug resistance. All the result provides reference to optimize clinical treatment schedule.
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. guowei0922@126.com.|NO. 201 hospital of the People's Liberation Army of China, Liaoyang, China. guowei0922@126.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. hanjingwan@outlook.com.
authors.forename: Jingwan
authors.initials: J
authors.lastname: Han
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. zdm0705@hotmail.com.
authors.forename: Daomin
authors.initials: D
authors.lastname: Zhuang
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. aliusy_0@sina.com.
authors.forename: Siyang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. yongjian325@sina.com.
authors.forename: Yongjian
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. dearwood@sina.com.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. hanpingline@163.com.
authors.forename: Hanping
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. ysmx_2000@sina.com.
authors.forename: Zuoyi
authors.initials: Z
authors.lastname: Bao
authors.affiliation: NO. 201 hospital of the People's Liberation Army of China, Liaoyang, China. 3668583@126.com.
authors.forename: Fujiang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of AIDS Research, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 20 Dongda Street, Fengtai District, Beijing, 100071, China. lijy@nic.bmi.ac.cn.
authors.forename: Jingyun
authors.initials: J
authors.lastname: Li
mesh_terms: D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology*; D018791:CD4 Lymphocyte Count; D002681:China; D024882:Drug Resistance, Viral; D019143:Evolution, Molecular; D015658:HIV Infections / Q000821:virology*; D054303:HIV Reverse Transcriptase / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D020125:Mutation, Missense; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase