The purpose of this study was to determine if the SV40-transformed murine macrophage cell line IC-21 is a suitable model to study the selective high avidity binding of tumor cells by subpopulations of activated macrophages. IC-21 macrophages bound P815, RBL5, and EL-4 murine tumor cells with high avidity, as measured by the inverted centrifugation method. Tumor binding by IC-21 macrophages was ...

BACKGROUND Recent infection testing algorithms (RITAs) are used in public health surveillance to estimate the incidence of recently acquired HIV-1 infection. OBJECTIVES Our aims were (i) to evaluate the precision of the VITROS® Anti-HIV 1+2 automated antibody avidity assay for qualitative detection of antibodies to HIV 1+2 virus; (ii) to validate the accuracy of an automated guanidine-based a...

During the progression of the clinical onset of Type 1 Diabetes (T1D), high-risk individuals exhibit multiple islet autoantibodies and high-avidity T cells which progressively destroy beta cells causing overt T1D. In particular, novel autoantibodies, such as those against IA-2 epitopes (aa1-577), had a predictive rate of 100% in a 10-year follow up (rapid progressors), unlike conventional autoa...

Central tolerance plays a significant role in preventing autoimmune diseases by eliminating T cells with high and intermediate avidity for self. To determine the manner of setting the threshold for deletion, we created a unique transgenic mouse strain with a diverse T cell population and globally increased TCR avidity for self-peptide/MHC complexes. Despite the adaptations aimed at reducing T c...

Decline of cell-mediated immunity is often attributed to decaying T-cell numbers and their distribution in peripheral organs. This study examined the hypothesis that qualitative as well as quantitative changes contribute to the declining efficacy of CD8(+) T-cell memory. Using a model of influenza virus infection, where loss of protective CD8(+) T-cell immunity was observed 6 months postinfec...

Cytotoxic T lymphocytes (CTLs) play a dominant role in the pathogenesis of autoimmune diabetes, commonly denoted Type 1 Diabetes (T1D). These CTLs (notably CD8(+) T cells) recognize and kill insulin-secreting pancreatic beta cells, reducing their number by approximately 90%. The resulting reduction of insulin secretion causes the defective regulation of glucose metabolism, leading to the charac...

It was recently shown that perceiving the avidity of T cell activation can be translated into peripheral T cell regulation to control autoimmune disease. This regulation is achieved by CD8(+) T cells that recognize a common surrogate target structure, Qa-1/Hsp60sp, preferentially expressed by activated T cells of intermediate but not high avidity. A truncated self-reactive repertoire, devoid of...

Determination of antibody avidity measurements can be difficult in human serum depending on the population evaluated. We evaluated three approaches for the determination of antibody avidity for immunoglobulin G (IgG). These approaches were (i) elution of bound antibody with increasing concentrations of a chaotropic agent using a single serum dilution, (ii) binding interference of multiple serum...

Effective T cell responses can decisively influence the outcome of retroviral infection. However, what constitutes protective T cell responses or determines the ability of the host to mount such responses is incompletely understood. Here we studied the requirements for development and induction of CD4+ T cells that were essential for immunity to Friend virus (FV) infection of mice, according to...

The dissemination of HIV from an initial site of infection is facilitated by motile HIV-infected CD4(+) T-cells. However, the impact of infected target cell migration on antigen recognition by HIV-specific CD8(+) T-cells is unclear. Using a 3D in vitro model of tissue, we visualized dynamic interactions between HIV-infected or peptide-pulsed CD4(+) T-cells and HIV-specific CD8(+) T-cells. CTLs ...