Bio


Following two years working in clinical trials Dr Cocker started his PhD under the supervision of Professor Mark Johnson and Dr Nesrina Imami, studying the impact of HIV-1 infection on pregnancy related immunological changes using fluorescent cytometry and functional assays to explore natural killer, dendritic and T cell populations longitudinally.
Dr Cocker is continuing his work in HIV and other infectious diseases, and is especially focussed on how chronic infection can effect natural killer cell education, development and function.

Professional Education


  • Bachelor of Science, University Of Leeds (2012)
  • Doctor of Philosophy, Imperial College of Science, Technology & Medicine (2019)

Stanford Advisors


All Publications


  • Pregnancy Gestation Impacts on HIV-1-Specific Granzyme B Response and Central Memory CD4 T Cells FRONTIERS IN IMMUNOLOGY Cocker, A. H., Shah, N. M., Raj, I., Dermont, S., Khan, W., Mandalia, S., Imami, N., Johnson, M. R. 2020; 11: 153

    Abstract

    Pregnancy induces alterations in peripheral T-cell populations with both changes in subset frequencies and anti-viral responses found to alter with gestation. In HIV-1 positive women anti-HIV-1 responses are associated with transmission risk, however detailed investigation into both HIV-1-specific memory responses associated with HIV-1 control and T-cell subset changes during pregnancy have not been undertaken. In this study we aimed to define pregnancy and gestation related changes to HIV-1-specific responses and T-cell phenotype in ART treated HIV-1 positive pregnant women. Eleven non-pregnant and 24 pregnant HIV-1 positive women were recruited, peripheral blood samples taken, fresh cells isolated, and compared using ELISpot assays and flow cytometry analysis. Clinical data were collected as part of standard care, and non-parametric statistics used. Alterations in induced IFNγ, IL-2, IL-10, and granzyme B secretion by peripheral blood mononuclear cells in response to HIV-1 Gag and Nef peptide pools and changes in T-cell subsets between pregnant and non-pregnant women were assessed, with data correlated with participant clinical parameters and longitudinal analysis performed. Cross-sectional comparison identified decreased IL-10 Nef response in HIV-1 positive pregnant women compared to non-pregnant, while correlations exhibited reversed Gag and Nef cytokine and protease response associations between groups. Longitudinal analysis of pregnant participants demonstrated transient increases in Gag granzyme B response and in the central memory CD4 T-cell subset frequency during their second trimester, with a decrease in CD4 effector memory T cells from their second to third trimester. Gag and Nef HIV-1-specific responses diverge with pregnancy time-point, coinciding with relevant T-cell phenotype, and gestation associated immunological adaptations. Decreased IL-10 Nef and both increased granzyme B Gag response and central memory CD4 T cells implies that amplified antigen production is occurring, which suggests a period of compromised HIV-1 control in pregnancy.

    View details for DOI 10.3389/fimmu.2020.00153

    View details for Web of Science ID 000518026700001

    View details for PubMedID 32117291

    View details for PubMedCentralID PMC7027986

  • Short Communication: Therapeutic Immunization Benefits Mucosal-Associated Invariant T Cell Recovery in Contrast to Interleukin-2, Granulocyte-Macrophage Colony-Stimulating Factor, and Recombinant Human Growth Hormone Addition in HIV-1+Treated Patients: Individual Case Reports from Phase I Trial AIDS RESEARCH AND HUMAN RETROVIRUSES Cocker, A. H., Greathead, L., Herasimtschuk, A. A., Mandalia, S., Kelleher, P., Imami, N. 2019; 35 (3): 306–9

    Abstract

    Mucosal-associated invariant T (MAIT) cell populations are reduced in frequency in HIV-1+ patients, and this disruption is associated with systemic immune activation. Reconstitution of MAIT frequency may benefit HIV-1-infected individuals; however, only recently has in vivo work been endeavored. Treatment with interleukin (IL)-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), and recombinant human growth hormone (rhGH) immunotherapy combined with an HIV-1 vaccine in the context of antiretroviral therapy (ART) has shown to reconstitute CD4 T cell population numbers and function. In this study cryopreserved peripheral blood mononuclear cells (PBMCs) from 12 HIV-1+ patients who were undergoing a combination of HIV-1 vaccine and/or IL-2, GM-CSF and rhGH immunotherapy in conjunction with ART were analyzed to assess the potential of this treatment to promote MAIT cell proliferation. PBMCs were thawed from study baseline, weeks 2 and 48 time points, fluorescently stained for MAIT cell markers, and assessed by flow cytometric analysis. Matched pairs and intergroup results were statistically compared using appropriate methods. MAIT cell frequency was increased from baseline at 48 weeks in participants who received vaccine only, whereas individuals receiving IL-2, GM-CSF, and rhGH immunotherapy with or without vaccine did not show additional benefit. Although IL-2, GM-CSF, and rhGH treatment promotes CD4 T cell reconstitution and HIV-1-specific T cell function, it does not support MAIT cell recovery in patients on suppressive ART. Therapeutic immunization however has a positive effect, highlighting the importance of aiming for balanced promotion of T cell population reconstitution to impact on HIV-1 transmission and pathogenesis.

    View details for DOI 10.1089/aid.2018.0176

    View details for Web of Science ID 000463903000012

    View details for PubMedID 30600702

  • Enrichment of HLA Types and Single-Nucleotide Polymorphism Associated With Non-progression in a Strictly Defined Cohort of HIV-1 Controllers. Frontiers in immunology Westrop, S. J., Cocker, A. T., Boasso, A., Sullivan, A. K., Nelson, M. R., Imami, N. 2017; 8: 746

    Abstract

    HIV-1 controllers (HIC) are extremely rare patients with the ability to control viral replication, maintain unchanging CD4 T-cell count, and evade disease progression for extensive periods of time, in the absence of antiretroviral therapy. In order to establish the representation of key genetic correlates of atypical disease progression within a cohort of HIV-1+ individuals who control viral replication, we examine four-digit resolution HLA type and single-nucleotide polymorphisms (SNP) previously identified to be correlated to non-progressive infection, in strictly defined HIC. Clinical histories were examined to identify patients exhibiting HIC status. Genomic DNA was extracted, and high definition HLA typing and genome-wide SNP analysis was performed. Data were compared with frequencies of SNP in European long-term non-progressors (LTNP) and primary infection cohorts. HLA-B alleles associated with atypical disease progression were at very high frequencies in the group of five HIC studied. All four HIC of European ancestry were HLA-B*57+ and half were also HLA-B*27+. All HIC, including one of self-reported African ethnicity, had the HLA-Cw*0602 allele, and the HLA-DQ9 allele was present only in HIC of European ancestry. A median 95% of the top 19 SNP known to be associated with LTNP status was observed in European HIC (range 78-100%); 17/19 of the SNP considered mapped to chromosome 6 in the HLA region, whereas 2/19 mapped to chromosome 8. The HIC investigated here demonstrated high enrichment of HLA types and SNP previously associated with long-term non-progression. These findings suggest that the extreme non-progressive phenotype considered here is associated with a genetic signature characterized by a single-genetic unit centered around the HLA-B*57 haplotype and the possible additive effect of HLA-B*27.

    View details for DOI 10.3389/fimmu.2017.00746

    View details for PubMedID 28702030

    View details for PubMedCentralID PMC5484768

  • A stepwise advance out of the shadows: leading HIV to its clearance FUTURE VIROLOGY Hardy, G. D., Cocker, A. H., Imami, N. 2015; 10 (12): 1263–66

    View details for DOI 10.2217/fvl.15.100

    View details for Web of Science ID 000366551800002