Limits...
Abacavir-reactive memory T cells are present in drug naïve individuals.

Lucas A, Lucas M, Strhyn A, Keane NM, McKinnon E, Pavlos R, Moran EM, Meyer-Pannwitt V, Gaudieri S, D'Orsogna L, Kalams S, Ostrov DA, Buus S, Peters B, Mallal S, Phillips E - PLoS ONE (2015)

Bottom Line: Fifty-five percent of individuals with HLA-B*57:01 exposed to the antiretroviral drug abacavir develop a hypersensitivity reaction (HSR) that has been attributed to naïve T-cell responses to neo-antigen generated by the drug.Abacavir reactive CD8+ T-cell responses were detected in vitro in one hundred percent of abacavir unexposed HLA-B*57:01 positive healthy donors.Abacavir-specific CD8+ T cells from such donors can be expanded from sorted memory, and sorted naïve, CD8+ T cells without need for autologous CD4+ T cells.

View Article: PubMed Central - PubMed

Affiliation: Institute for Immunology and Infectious Diseases, Murdoch University, Perth, Australia.

ABSTRACT

Background: Fifty-five percent of individuals with HLA-B*57:01 exposed to the antiretroviral drug abacavir develop a hypersensitivity reaction (HSR) that has been attributed to naïve T-cell responses to neo-antigen generated by the drug. Immunologically confirmed abacavir HSR can manifest clinically in less than 48 hours following first exposure suggesting that, at least in some cases, abacavir HSR is due to re-stimulation of a pre-existing memory T-cell population rather than priming of a high frequency naïve T-cell population.

Methods: To determine whether a pre-existing abacavir reactive memory T-cell population contributes to early abacavir HSR symptoms, we studied the abacavir specific naïve or memory T-cell response using HLA-B*57:01 positive HSR patients or healthy controls using ELISpot assay, intra-cellular cytokine staining and tetramer labelling.

Results: Abacavir reactive CD8+ T-cell responses were detected in vitro in one hundred percent of abacavir unexposed HLA-B*57:01 positive healthy donors. Abacavir-specific CD8+ T cells from such donors can be expanded from sorted memory, and sorted naïve, CD8+ T cells without need for autologous CD4+ T cells.

Conclusions: We propose that these pre-existing abacavir-reactive memory CD8+ T-cell responses must have been primed by earlier exposure to another foreign antigen and that these T cells cross-react with an abacavir-HLA-B*57:01-endogenous peptide ligand complex, in keeping with the model of heterologous immunity proposed in transplant rejection.

Show MeSH

Related in: MedlinePlus

Abacavir responsive CD8+ T cells detected in HLA-B*57:01+ abacavir-unexposed donors.HLA-B*57:01+ (n = 3) from abacavir unexposed donors were stimulated for 5h with 1:10 C1R.B57 APC (left column) or abacavir treated C1R.B57 APC (right column), and CD8+/ IFN-γ+ cells detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donors 1 (A, B) and 2 (C, D) are the results from cryopreserved PBMC. Donor 3 (E, F) is the result of a freshly separated PBMC sample. Similarly, HLA-B*57:01 negative PBMC (n = 2) from abacavir unexposed donors were stimulated for 5h with 1:10 fractions of autologous PBMC (PBMC: left column) or autologous PBMC treated with abacavir (PBMC.ABC: right column) and CD8+/IFN-γ cell detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donor 4 (G, H) and Donor 5 (I, J) are the results from cryopreserved PBMC.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4326126&req=5

pone.0117160.g003: Abacavir responsive CD8+ T cells detected in HLA-B*57:01+ abacavir-unexposed donors.HLA-B*57:01+ (n = 3) from abacavir unexposed donors were stimulated for 5h with 1:10 C1R.B57 APC (left column) or abacavir treated C1R.B57 APC (right column), and CD8+/ IFN-γ+ cells detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donors 1 (A, B) and 2 (C, D) are the results from cryopreserved PBMC. Donor 3 (E, F) is the result of a freshly separated PBMC sample. Similarly, HLA-B*57:01 negative PBMC (n = 2) from abacavir unexposed donors were stimulated for 5h with 1:10 fractions of autologous PBMC (PBMC: left column) or autologous PBMC treated with abacavir (PBMC.ABC: right column) and CD8+/IFN-γ cell detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donor 4 (G, H) and Donor 5 (I, J) are the results from cryopreserved PBMC.

Mentions: We examined whether the rapid and early clinical responses to abacavir in some patients could be explained by expansion of pre-existing memory CD8+ T cells by exposing PBMC from abacavir-unexposed HLA-B*57:01 positive (n = 3) and negative donors (n = 2) to APC stimulation with either the HLA-B*57:01 transfected single HLA antigen cell line C1R.B57 or autologous PBMC, ± abacavir (Fig. 3). We used a five hour IFN-γ capture assay to measure IFN-γ responses. A low frequency of abacavir responsive CD8+/IFN-γ+ T cells were detected within PBMC from three of three abacavir unexposed HLA-B*57:01 positive donors stimulated with abacavir treated C1R.B57 APC (Fig. 3: right column) compared to untreated C1R.B57 (Fig. 3: left column). The abacavir responsive CD8+/IFN-γ+ T cells were detectable above background in two cryopreserved HLA-B*57:01 donor samples (Fig. 3: A compared to B, C compared to D) and also in freshly separated PBMC (Fig. 3: E compared to F). No comparable increase in CD8+ IFN-γ + T cells were detected above background in two of two HLA-B*57:01 negative donors stimulated with abacavir treated autologous PBMC (Fig. 3: G compared to H and I compared to J).


Abacavir-reactive memory T cells are present in drug naïve individuals.

Lucas A, Lucas M, Strhyn A, Keane NM, McKinnon E, Pavlos R, Moran EM, Meyer-Pannwitt V, Gaudieri S, D'Orsogna L, Kalams S, Ostrov DA, Buus S, Peters B, Mallal S, Phillips E - PLoS ONE (2015)

Abacavir responsive CD8+ T cells detected in HLA-B*57:01+ abacavir-unexposed donors.HLA-B*57:01+ (n = 3) from abacavir unexposed donors were stimulated for 5h with 1:10 C1R.B57 APC (left column) or abacavir treated C1R.B57 APC (right column), and CD8+/ IFN-γ+ cells detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donors 1 (A, B) and 2 (C, D) are the results from cryopreserved PBMC. Donor 3 (E, F) is the result of a freshly separated PBMC sample. Similarly, HLA-B*57:01 negative PBMC (n = 2) from abacavir unexposed donors were stimulated for 5h with 1:10 fractions of autologous PBMC (PBMC: left column) or autologous PBMC treated with abacavir (PBMC.ABC: right column) and CD8+/IFN-γ cell detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donor 4 (G, H) and Donor 5 (I, J) are the results from cryopreserved PBMC.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4326126&req=5

pone.0117160.g003: Abacavir responsive CD8+ T cells detected in HLA-B*57:01+ abacavir-unexposed donors.HLA-B*57:01+ (n = 3) from abacavir unexposed donors were stimulated for 5h with 1:10 C1R.B57 APC (left column) or abacavir treated C1R.B57 APC (right column), and CD8+/ IFN-γ+ cells detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donors 1 (A, B) and 2 (C, D) are the results from cryopreserved PBMC. Donor 3 (E, F) is the result of a freshly separated PBMC sample. Similarly, HLA-B*57:01 negative PBMC (n = 2) from abacavir unexposed donors were stimulated for 5h with 1:10 fractions of autologous PBMC (PBMC: left column) or autologous PBMC treated with abacavir (PBMC.ABC: right column) and CD8+/IFN-γ cell detected by IFN-γ capture assay and enumerated by flow cytometry. Cells that fall within the depicted gates are considered positive. Donor 4 (G, H) and Donor 5 (I, J) are the results from cryopreserved PBMC.
Mentions: We examined whether the rapid and early clinical responses to abacavir in some patients could be explained by expansion of pre-existing memory CD8+ T cells by exposing PBMC from abacavir-unexposed HLA-B*57:01 positive (n = 3) and negative donors (n = 2) to APC stimulation with either the HLA-B*57:01 transfected single HLA antigen cell line C1R.B57 or autologous PBMC, ± abacavir (Fig. 3). We used a five hour IFN-γ capture assay to measure IFN-γ responses. A low frequency of abacavir responsive CD8+/IFN-γ+ T cells were detected within PBMC from three of three abacavir unexposed HLA-B*57:01 positive donors stimulated with abacavir treated C1R.B57 APC (Fig. 3: right column) compared to untreated C1R.B57 (Fig. 3: left column). The abacavir responsive CD8+/IFN-γ+ T cells were detectable above background in two cryopreserved HLA-B*57:01 donor samples (Fig. 3: A compared to B, C compared to D) and also in freshly separated PBMC (Fig. 3: E compared to F). No comparable increase in CD8+ IFN-γ + T cells were detected above background in two of two HLA-B*57:01 negative donors stimulated with abacavir treated autologous PBMC (Fig. 3: G compared to H and I compared to J).

Bottom Line: Fifty-five percent of individuals with HLA-B*57:01 exposed to the antiretroviral drug abacavir develop a hypersensitivity reaction (HSR) that has been attributed to naïve T-cell responses to neo-antigen generated by the drug.Abacavir reactive CD8+ T-cell responses were detected in vitro in one hundred percent of abacavir unexposed HLA-B*57:01 positive healthy donors.Abacavir-specific CD8+ T cells from such donors can be expanded from sorted memory, and sorted naïve, CD8+ T cells without need for autologous CD4+ T cells.

View Article: PubMed Central - PubMed

Affiliation: Institute for Immunology and Infectious Diseases, Murdoch University, Perth, Australia.

ABSTRACT

Background: Fifty-five percent of individuals with HLA-B*57:01 exposed to the antiretroviral drug abacavir develop a hypersensitivity reaction (HSR) that has been attributed to naïve T-cell responses to neo-antigen generated by the drug. Immunologically confirmed abacavir HSR can manifest clinically in less than 48 hours following first exposure suggesting that, at least in some cases, abacavir HSR is due to re-stimulation of a pre-existing memory T-cell population rather than priming of a high frequency naïve T-cell population.

Methods: To determine whether a pre-existing abacavir reactive memory T-cell population contributes to early abacavir HSR symptoms, we studied the abacavir specific naïve or memory T-cell response using HLA-B*57:01 positive HSR patients or healthy controls using ELISpot assay, intra-cellular cytokine staining and tetramer labelling.

Results: Abacavir reactive CD8+ T-cell responses were detected in vitro in one hundred percent of abacavir unexposed HLA-B*57:01 positive healthy donors. Abacavir-specific CD8+ T cells from such donors can be expanded from sorted memory, and sorted naïve, CD8+ T cells without need for autologous CD4+ T cells.

Conclusions: We propose that these pre-existing abacavir-reactive memory CD8+ T-cell responses must have been primed by earlier exposure to another foreign antigen and that these T cells cross-react with an abacavir-HLA-B*57:01-endogenous peptide ligand complex, in keeping with the model of heterologous immunity proposed in transplant rejection.

Show MeSH
Related in: MedlinePlus