{"id":20815,"date":"2013-02-01T11:34:31","date_gmt":"2013-02-01T11:34:31","guid":{"rendered":"http:\/\/i-base.info\/htb\/?p=20815"},"modified":"2013-02-07T08:16:06","modified_gmt":"2013-02-07T08:16:06","slug":"attack-of-the-killer-helpers-part-two","status":"publish","type":"post","link":"https:\/\/i-base.info\/htb\/20815","title":{"rendered":"Attack of the killer helpers (part two)"},"content":{"rendered":"

Richard Jefferys, TAG<\/strong><\/p>\n

Among the many tasks of the immune system, the responsibility for recognising and killing virus-infected cells largely falls to the subset of CD8 T cells designated cytotoxic T-lymphocytes (CTL).<\/strong><\/p>\n

The question of whether CD4 T cells (traditionally called just “helper” cells) can exert cytotoxic functions has historically been controversial, but over the past decade, studies have convincingly documented the existence of cytotoxic CD4 T cell responses in a variety of different settings, including HIV and SIV infection (as previously covered on this blog). [1]<\/p>\n

A new paper in the open-access journal Retrovirology from Jonah Sacha’s research group at Oregon Health and Science University now reports that not only are cytotoxic CD4 T cell responses detectable in macaques controlling a pathogenic SIV isolate, but they can drive the selection of immune escape mutations. As the authors note, this represents compelling evidence that CD4 T cells can directly suppress viral replication. [2]<\/p>\n

Although it was not highlighted on the blog at the time of publication, a human study from the laboratory of Hendrick Streeck also argues for a key role of cytotoxic CD4 T cell responses in controlling HIV. [3]<\/p>\n

Published in Science Translational Medicine back in February of this year, the study showed that HIV-specific cytotoxic CD4 T cell activity predicted superior control of viral load and slower disease progression (as assessed by time to CD4 T cell count <350, time to ART initiation or time to viral load >100,000 copies) in a cohort of acutely HIV-infected individuals.<\/p>\n

Taken together, these results further underscore the importance of considering virus-specific CD4 T cell responses, both in studies of natural control of HIV replication and in attempts to design effective immune-based therapies.<\/p>\n

Source:<\/p>\n

TAG Basic Science Blog. Attack of the killer helpers (part two). (27 November 2012).<\/p>\n

References:<\/p>\n

    \n
  1. Killer helpers. Basic Science Blog (June 2009).
    \nhttp:\/\/tagbasicscienceproject.typepad.com\/tags_basic_science_vaccin\/2009\/06\/killer-helpers.html<\/a><\/li>\n
  2. Burwitz BJ et al. Retrovirology. 2012 Nov 6;9:91. doi: 10.1186\/1742-4690-9-91. CD8+ and CD4+ cytotoxic T cell escape mutations precede breakthrough SIVmac239 viremia in an elite controller. Retrovirology. 2012 Nov 6;9:91. doi: 10.1186\/1742-4690-9-91.
    \n    http:\/\/www.retrovirology.com\/content\/9\/1\/91<\/a><\/li>\n
  3. Soghoian DZ et al. HIV-specific cytolytic CD4 T cell responses during acute HIV infection predict disease outcome. Sci Transl Med. 2012 Feb 29;4(123):123ra25. doi: 10.1126\/scitranslmed.3003165.
    \n    http:\/\/stm.sciencemag.org\/content\/4\/123\/123ra25.short<\/a><\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

    Richard Jefferys, TAG Among the many tasks of the immune system, the responsibility for recognising and killing virus-infected cells largely falls to the subset of CD8 T cells designated cytotoxic T-lymphocytes (CTL). The question of whether CD4 T cells (traditionally …<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-20815","post","type-post","status-publish","format-standard","hentry","category-basic-science-and-immunology"],"_links":{"self":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/20815","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/comments?post=20815"}],"version-history":[{"count":0,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/posts\/20815\/revisions"}],"wp:attachment":[{"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/media?parent=20815"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/categories?post=20815"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i-base.info\/htb\/wp-json\/wp\/v2\/tags?post=20815"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}