The mechanisms by which the hepatitis C virus (HCV) establishes persistence are not yet fully understood. Previous chimpanzee and now human studies suggest that mutations within MHC class I-restricted HCV epitopes might contribute to viral escape from cytotoxic T lymphocyte (CTL) responses. However, there are several outstanding questions regarding the role of escape mutations in viral persiste...

Virus-specific cluster of differentiation 8 (CD8+) cytotoxic T cells (CTL) recognize viral antigens presented on major histocompatibility complex (MHC) class I chains on infected hepatocytes, with help from CD4+ T cells. However, this CTL response is frequently weak or undetectable in patients with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. Programmed cell death 1 (P...

Immunological synapses are organized cell-cell junctions between T lymphocytes and APCs composed of an adhesion ring, the peripheral supramolecular activation cluster (pSMAC), and a central T cell receptor cluster, the central supramolecular activation cluster (cSMAC). In CD8(+) cytotoxic T lymphocytes, the immunological synapse is thought to facilitate specific killing by confining cytotoxic a...

BACKGROUND The imidazoquinoline derivate imiquimod induces inflammatory responses and protection against transplanted tumors when applied to the skin in combination with a cognate peptide epitope (transcutaneous immunization, TCI). Here we investigated the role of regulatory T cells (T(reg)) and the suppressive cytokine IL-10 in restricting TCI-induced cytotoxic T lymphocyte (CTL) responses. ...

Monoclonal antibody 384.5 specifically inhibited cytolysis of P-815 target cells by cloned L3 cytotoxic T lymphocyte (CTL) effector cells. The lytic activity of other cloned CTL that have other distinct specificities was not affected. Antibody 384.5 did not inhibit the cytolytic activity of bulk populations of C57BL/6 mixed lymphocyte culture (MLC) cells. Concanavalin A-facilitated cytolysis by...

We have tested the abilities of various polypeptides of A/PR/8/34 (H1N1) virus, constructed by recombinant DNA techniques, to induce influenza virus-specific secondary cytotoxic T lymphocyte (CTL) responses. A hybrid protein (c13 protein), consisting of the first 81 amino acids of viral nonstructural protein (NS1) and the HA2 subunit of viral hemagglutinin (HA), induced H-2-restricted, influenz...

In the present study we used hydrocortisone (HC) treatment in vivo as a probe to analyze two different in vitro systems for the regeneration of cytotoxic T lymphocyte (CTL), namely the antifibroblast reaction (AFR) and the mixed lymphocyte culture (MLC) system. We found that cells remaining in the thymus after HC treatment had increased reactivity in these two systems. However, the same treatme...

Despite detailed analysis of the HIV-1–specific cytotoxic T lymphocyte response by various groups, its relation to viral load and viral sequence variation remains controversial. We analyzed HLA-A*0201 restricted cytotoxic T lymphocyte responses in 17 HIV-1–infected individuals with viral loads ranging from , 400 to 221,000 HIV RNA molecules per milliliter of plasma. In 13 out of 17 infected sub...

The prevalence of human cytomegalovirus (HCMV) pp65-, pp150-, IE1-exon4-, gB- and pp28-specific cytotoxic T lymphocyte (CTL) responses was compared among 34 healthy individuals, grouped by neutralizing antibody titers. Moderately and highly seropositive donors showed predominantly pp65- and IE1-exon4-specific CTL responses (92% and 76% of the donors, respectively), with similar precursor freque...

Escape from cytotoxic T-lymphocyte (CTL) pressure is common in HIV-1 infection of humans and simian immunodeficiency virus (SIV) infections of macaques. CTL escape typically incurs a fitness cost as reversion back to wild-type can occur upon transmission. We utilized sequence-specific primers and DNA probes with real-time polymerase chain reaction (PCR) to sensitively and specifically track wil...