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Clustered mutations in HIV-1 gag are consistently required for escape from HLA-B27-restricted cytotoxic T lymphocyte responses.

Kelleher AD, Long C, Holmes EC, Allen RL, Wilson J, Conlon C, Workman C, Shaunak S, Olson K, Goulder P, Brander C, Ogg G, Sullivan JS, Dyer W, Jones I, McMichael AJ, Rowland-Jones S, Phillips RE - J. Exp. Med. (2001)

Bottom Line: In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype.In each case, R264K was tightly associated with a leucine to methionine change at residue 268.Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Human Immunology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom. kelleher@worf.molbiol.ox.ac.uk

ABSTRACT
The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263-272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein.

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Time course of four subjects developing nonbinding mutations: (a) 777, (b) SW, (c) 007, and (d) RT. In each, the top panel shows CD4+ count (left axis) and HLA B-27 tetramer staining (right axis); the middle panel shows viral load (log RNA copies/ml); and the bottom panel shows the percentage of clones with each variant epitope sequence. Top panels: filled boxes, CD4+ T cell count; open triangles, percentage of CD8+ cells staining with M268 variant peptide B27 tetramer; open diamonds, percentage of CD8+ cells staining with L268 variant peptide B27 tetramer. Double-headed arrows indicate period during which fresh killing was detected of peptide-pulsed autologous targets. Middle panels: closed circles, viral load log10 copies of HIV RNA/ml plasma. Periods of mononucleoside analogue therapy (MT), dual nucleoside analogue therapy (DT), and combination therapy with dual nucleoside analogues and a protease inhibitor (CAC) are indicated by double arrow headed lines. Bottom panels: white bars, percentage of viral DNA sequences with R264 M268; gray bars, percentage of viral DNA sequences with E260 R264 L268 (w/t); black bars, percentage of viral DNA sequences with K264 M268; horizontal stripe, percentage of viral DNA sequences with K264 L268; left to right downward hatch, percentage of viral DNA sequences with D260 G264 L268; and right to left downward hatch, percentage of viral DNA sequences with another mutation at 264.
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Figure 1: Time course of four subjects developing nonbinding mutations: (a) 777, (b) SW, (c) 007, and (d) RT. In each, the top panel shows CD4+ count (left axis) and HLA B-27 tetramer staining (right axis); the middle panel shows viral load (log RNA copies/ml); and the bottom panel shows the percentage of clones with each variant epitope sequence. Top panels: filled boxes, CD4+ T cell count; open triangles, percentage of CD8+ cells staining with M268 variant peptide B27 tetramer; open diamonds, percentage of CD8+ cells staining with L268 variant peptide B27 tetramer. Double-headed arrows indicate period during which fresh killing was detected of peptide-pulsed autologous targets. Middle panels: closed circles, viral load log10 copies of HIV RNA/ml plasma. Periods of mononucleoside analogue therapy (MT), dual nucleoside analogue therapy (DT), and combination therapy with dual nucleoside analogues and a protease inhibitor (CAC) are indicated by double arrow headed lines. Bottom panels: white bars, percentage of viral DNA sequences with R264 M268; gray bars, percentage of viral DNA sequences with E260 R264 L268 (w/t); black bars, percentage of viral DNA sequences with K264 M268; horizontal stripe, percentage of viral DNA sequences with K264 L268; left to right downward hatch, percentage of viral DNA sequences with D260 G264 L268; and right to left downward hatch, percentage of viral DNA sequences with another mutation at 264.

Mentions: Patient 777 was identified 14 d after a high risk exposure with fever, headache and esophageal candidiasis. His HIV RNA was >106 copies/ml of plasma. He declined antiretroviral therapy. Viral loads and CD4+ counts are shown in Fig. 1. During symptomatic infection viral sequences were w/t at position 264 (R264) and showed methionine (M), rather than leucine (L) at position 268 (Fig. 1 a, and online supplemental Table SI). 28 wk later, his virus contained a mixture of both M268 and L268, but retained R264 in all sequences. 52 wk after acquiring infection, 96% of his viral sequences carried the R264K sequence (1/25 had R264I) and all had M268. Combination antiretroviral chemotherapy (CAC) was instituted at this visit because of persistent viremia and the development of a virus with a syncytium-inducing phenotype (SI). Viremia was better controlled after therapy and a mixed population of viral sequences was detected (Fig. 1 a, and online supplemental Table SI). Throughout the period of observation, this patient had a robust HLA-B27–restricted immunodominant CD8+ T cell response to p24 gag (263–272) as detected by tetramer staining (Fig. 1 a).


Clustered mutations in HIV-1 gag are consistently required for escape from HLA-B27-restricted cytotoxic T lymphocyte responses.

Kelleher AD, Long C, Holmes EC, Allen RL, Wilson J, Conlon C, Workman C, Shaunak S, Olson K, Goulder P, Brander C, Ogg G, Sullivan JS, Dyer W, Jones I, McMichael AJ, Rowland-Jones S, Phillips RE - J. Exp. Med. (2001)

Time course of four subjects developing nonbinding mutations: (a) 777, (b) SW, (c) 007, and (d) RT. In each, the top panel shows CD4+ count (left axis) and HLA B-27 tetramer staining (right axis); the middle panel shows viral load (log RNA copies/ml); and the bottom panel shows the percentage of clones with each variant epitope sequence. Top panels: filled boxes, CD4+ T cell count; open triangles, percentage of CD8+ cells staining with M268 variant peptide B27 tetramer; open diamonds, percentage of CD8+ cells staining with L268 variant peptide B27 tetramer. Double-headed arrows indicate period during which fresh killing was detected of peptide-pulsed autologous targets. Middle panels: closed circles, viral load log10 copies of HIV RNA/ml plasma. Periods of mononucleoside analogue therapy (MT), dual nucleoside analogue therapy (DT), and combination therapy with dual nucleoside analogues and a protease inhibitor (CAC) are indicated by double arrow headed lines. Bottom panels: white bars, percentage of viral DNA sequences with R264 M268; gray bars, percentage of viral DNA sequences with E260 R264 L268 (w/t); black bars, percentage of viral DNA sequences with K264 M268; horizontal stripe, percentage of viral DNA sequences with K264 L268; left to right downward hatch, percentage of viral DNA sequences with D260 G264 L268; and right to left downward hatch, percentage of viral DNA sequences with another mutation at 264.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2195921&req=5

Figure 1: Time course of four subjects developing nonbinding mutations: (a) 777, (b) SW, (c) 007, and (d) RT. In each, the top panel shows CD4+ count (left axis) and HLA B-27 tetramer staining (right axis); the middle panel shows viral load (log RNA copies/ml); and the bottom panel shows the percentage of clones with each variant epitope sequence. Top panels: filled boxes, CD4+ T cell count; open triangles, percentage of CD8+ cells staining with M268 variant peptide B27 tetramer; open diamonds, percentage of CD8+ cells staining with L268 variant peptide B27 tetramer. Double-headed arrows indicate period during which fresh killing was detected of peptide-pulsed autologous targets. Middle panels: closed circles, viral load log10 copies of HIV RNA/ml plasma. Periods of mononucleoside analogue therapy (MT), dual nucleoside analogue therapy (DT), and combination therapy with dual nucleoside analogues and a protease inhibitor (CAC) are indicated by double arrow headed lines. Bottom panels: white bars, percentage of viral DNA sequences with R264 M268; gray bars, percentage of viral DNA sequences with E260 R264 L268 (w/t); black bars, percentage of viral DNA sequences with K264 M268; horizontal stripe, percentage of viral DNA sequences with K264 L268; left to right downward hatch, percentage of viral DNA sequences with D260 G264 L268; and right to left downward hatch, percentage of viral DNA sequences with another mutation at 264.
Mentions: Patient 777 was identified 14 d after a high risk exposure with fever, headache and esophageal candidiasis. His HIV RNA was >106 copies/ml of plasma. He declined antiretroviral therapy. Viral loads and CD4+ counts are shown in Fig. 1. During symptomatic infection viral sequences were w/t at position 264 (R264) and showed methionine (M), rather than leucine (L) at position 268 (Fig. 1 a, and online supplemental Table SI). 28 wk later, his virus contained a mixture of both M268 and L268, but retained R264 in all sequences. 52 wk after acquiring infection, 96% of his viral sequences carried the R264K sequence (1/25 had R264I) and all had M268. Combination antiretroviral chemotherapy (CAC) was instituted at this visit because of persistent viremia and the development of a virus with a syncytium-inducing phenotype (SI). Viremia was better controlled after therapy and a mixed population of viral sequences was detected (Fig. 1 a, and online supplemental Table SI). Throughout the period of observation, this patient had a robust HLA-B27–restricted immunodominant CD8+ T cell response to p24 gag (263–272) as detected by tetramer staining (Fig. 1 a).

Bottom Line: In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype.In each case, R264K was tightly associated with a leucine to methionine change at residue 268.Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council Human Immunology Unit, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford OX3 9DS, United Kingdom. kelleher@worf.molbiol.ox.ac.uk

ABSTRACT
The immune response to HIV-1 in patients who carry human histocompatibility leukocyte antigen (HLA)-B27 is characterized by an immunodominant response to an epitope in p24 gag (amino acids 263-272, KRWIILGLNK). Substitution of lysine (K) or glycine (G) for arginine (R) at HIV-1 gag residue 264 (R264K and R264G) results in epitopes that bind to HLA-B27 poorly. We have detected a R264K mutation in four patients carrying HLA-B27. In three of these patients the mutation occurred late, coinciding with disease progression. In another it occurred within 1 yr of infection and was associated with a virus of syncytium-inducing phenotype. In each case, R264K was tightly associated with a leucine to methionine change at residue 268. After the loss of the cytotoxic T lymphocyte (CTL) response to this epitope and in the presence of high viral load, reversion to wild-type sequence was observed. In a fifth patient, a R264G mutation was detected when HIV-1 disease progressed. Its occurrence was associated with a glutamic acid to aspartic acid mutation at residue 260. Phylogenetic analyses indicated that these substitutions emerged under natural selection rather than by genetic drift or linkage. Outgrowth of CTL escape viruses required high viral loads and additional, possibly compensatory, mutations in the gag protein.

Show MeSH
Related in: MedlinePlus