Antiviral CD8+ T Cells Restricted by Human Leukocyte Antigen Class II Exist during Natural HIV Infection and Exhibit Clonal Expansion.

CD8+ T cell recognition of virus-infected cells is characteristically restricted by major histocompatibility complex (MHC) class I, although rare examples of MHC class II restriction have been reported in Cd4-deficient mice and a macaque SIV vaccine trial using a recombinant cytomegalovirus vector. Here, we demonstrate the presence of human leukocyte antigen (HLA) class II-restricted CD8+ T cell responses with antiviral properties in a small subset of HIV-infected individuals. In these individuals, T cell receptor ß (TCRß) analysis revealed that class II-restricted CD8+ T cells underwent clonal expansion and mediated killing of HIV-infected cells. In one case, these cells comprised 12% of circulating CD8+ T cells, and TCRα analysis revealed two distinct co-expressed TCRα chains, with only one contributing to binding of the class II HLA-peptide complex. These data indicate that class II-restricted CD8+ T cell responses can exist in a chronic human viral infection, and may contribute to immune control.

Recognition and management of clozapine adverse effects: A systematic review and qualitative synthesis.

OBJECTIVE: Clozapine is substantially underutilized in most countries and clinician factors including lack of knowledge and concerns about adverse drug effects (ADEs) contribute strongly to treatment reluctance. The aim of this systematic review was to provide clinicians with a comprehensive information source regarding clozapine ADEs. METHODS: PubMed and Embase databases were searched for English language reviews concerned with clozapine ADEs; publications identified by the automated search were manually searched for additional relevant citations. Following exclusion of redundant and irrelevant reports, pertinent information was summarized in evidence tables corresponding to each of six major ADE domains; two authors reviewed all citations for each ADE domain and summarized their content by consensus in the corresponding evidence table. This study was conducted in accordance with PRISMA principles. RESULTS: Primary and secondary searches identified a total of 305 unique reports, of which 152 were included in the qualitative synthesis. Most clozapine ADEs emerge within 3 months, and almost all appear within 6 months, after initiation. Notable exceptions are weight gain, diabetic ketoacidosis (DKA), severe clozapine-induced gastrointestinal hypomotility (CIGH), clozapine-induced cardiomyopathy (CICM), seizures, and clozapine-induced neutropenia (CIN). Most clozapine ADEs subside gradually or respond to dose reduction; those that prompt discontinuation generally do not preclude rechallenge. Rechallenge is generally inadvisable for clozapine-induced myocarditis (CIM), CICM, and clozapine-induced agranulocytosis (CIA). Clozapine plasma levels >600-1000 µg/L appear more likely to cause certain ADEs (e.g., seizures) and, although there is no clear toxicity threshold, risk/benefit ratios are generally unfavorable above 1000 µg/L. CONCLUSION: Clozapine ADEs rarely require discontinuation.

HIV-1 Antibody Neutralization Breadth Is Associated with Enhanced HIV-Specific CD4+ T Cell Responses.

UNLABELLED: Antigen-specific CD4(+) T helper cell responses have long been recognized to be a critical component of effective vaccine immunity. CD4(+) T cells are necessary to generate and maintain humoral immune responses by providing help to antigen-specific B cells for the production of antibodies. In HIV infection, CD4(+) T cells are thought to be necessary for the induction of Env-specific broadly neutralizing antibodies. However, few studies have investigated the role of HIV-specific CD4(+) T cells in association with HIV neutralizing antibody activity in vaccination or natural infection settings. Here, we conducted a comprehensive analysis of HIV-specific CD4(+) T cell responses in a cohort of 34 untreated HIV-infected controllers matched for viral load, with and without neutralizing antibody breadth to a panel of viral strains. Our results show that the breadth and magnitude of Gag-specific CD4(+) T cell responses were significantly higher in individuals with neutralizing antibodies than in those without neutralizing antibodies. The breadth of Gag-specific CD4(+) T cell responses was positively correlated with the breadth of neutralizing antibody activity. Furthermore, the breadth and magnitude of gp41-specific, but not gp120-specific, CD4(+) T cell responses were significantly elevated in individuals with neutralizing antibodies. Together, these data suggest that robust Gag-specific CD4(+) T cells and, to a lesser extent, gp41-specific CD4(+) T cells may provide important intermolecular help to Env-specific B cells that promote the generation or maintenance of Env-specific neutralizing antibodies. IMPORTANCE: One of the earliest discoveries related to CD4(+) T cell function was their provision of help to B cells in the development of antibody responses. Yet little is known about the role of CD4(+) T helper responses in the setting of HIV infection, and no studies to date have evaluated the impact of HIV-specific CD4(+) T cells on the generation of antibodies that can neutralize multiple different strains of HIV. Here, we addressed this question by analyzing HIV-specific CD4(+) T cell responses in untreated HIV-infected persons with and without neutralizing antibodies. Our results indicate that HIV-infected persons with neutralizing antibodies have significantly more robust CD4(+) T cell responses targeting Gag and gp41 proteins than individuals who lack neutralizing antibodies. These associations suggest that Gag- and gp41-specific CD4(+) T cell responses may provide robust help to B cells for the generation or maintenance of neutralizing antibodies in natural HIV-infection.

Deletion of AIF1 but not of YCA1/MCA1 protects Saccharomyces cerevisiae and Candida albicans cells from caspofungin-induced programmed cell death.

Caspofungin was the first member of a new class of antifungals called echinocandins to be approved by a drug regulatory authority. Like the other echinocandins, caspofungin blocks the synthesis of ß(1,3)-D-glucan of the fungal cell wall by inhibiting the enzyme, ß(1,3)-D-glucan synthase. Loss of ß(1,3)-D-glucan leads to osmotic instability and cell death. However, the precise mechanism of cell death associated with the cytotoxicity of caspofungin was unclear. We now provide evidence that Saccharomyces cerevisiae cells cultured in media containing caspofungin manifest the classical hallmarks of programmed cell death (PCD) in yeast, including the generation of reactive oxygen species (ROS), the fragmentation of mitochondria, and the production of DNA strand breaks. Our data also suggests that deleting AIF1 but not YCA1/MCA1 protects S. cerevisiae and Candida albicans from caspofungin-induced cell death. This is not only the first time that AIF1 has been specifically tied to cell death in Candida but also the first time that caspofungin resistance has been linked to the cell death machinery in yeast.