Characterisation of CD8 monoclonal antibody-induced protection from diabetes in NOD mice

CD4/CD8 Antibodies Reduce Histopathological Damage in Salivary Glands of Spontaneously Diabetic Mice

Background and aims: Diabetes affects the metabolism promoting damage in different tissues, including salivary glands. Current treatments, such as insulin, are ineffective to recovery of these tissues. In this aspect, the immunotherapy has been tested, but it can be inefficient as an agent for the control of damage caused by diabetes. The aim of this study to evaluate the association in anti-CD4 and anti-CD8 monoclonal antibody in the recovery of salivary glands of diabetic NOD mice.

Material and methods: Fifteen spontaneously diabetic mice (NOD) were divided into three groups with 5 animals each: group I (Balb/C control mice), group II (untreated NOD mice), group III (NOD mice treated with CD4 and CD8 antibodies). The CD4 and CD8 antibodies (IMUNY, Rheabiotech Ltda, Brazil) were administered by intravenously injections (25 ug/days: 0, 7, 14, and 21). After treatment salivary glands samples were analyzed by immunofluorescence, microscopy, light microscopy and stereology. (ethical approval process: 304/11), Analysis of variance (ANOVA) and Kruskal-Wallis nonparametric test were used.

Results: Elevated levels of glucose (mg/dl) were observed in untreated animals (group II) (605.25 ± 31.23, p≤0.05), whereas in treated animals (group III), were noted a decrease in these levels (464.77 ± 39.66, p≤0.05). Tissue restructure, characterized by cell volume recovery, also was observed in group III (nuclear volume of parotid glands: (109.91 ± 02.03, p≤0.05) and submandibular glands: (107.52 ± 02, p≤0.05) (cytoplasmic volume of parotid glands: (356.14 ± 26.34, p≤0.05) and submandibular glands: (331.22 ± 32.11, p≤0.05). Intense signaling (+++) of insulin receptors was observed in animals of group I. On the other hand, in group II was noted a reduction of these receptors (+). In treated animals (group III) were observed a recovery of the insulin receptors (+++).

Conclusions: This treatment was effective in the recovery of salivary acinar cells, contributed also to homeostasis of body metabolism. Thus, this immunomodulation promoted a beneficial effect on the recovery of these tissues.

Anti-CD8 monoclonal antibody-mediated depletion alters the phenotype and behavior of surviving CD8+ T cells

It is common practice for researchers to use antibodies to remove a specific cell type to infer its function. However, it is difficult to completely eliminate a cell type and there is often limited or no information as to how the cells which survive depletion are affected. This is particularly important for CD8+ T cells for two reasons. First, they are more resistant to mAb-mediated depletion than other lymphocytes. Second, targeting either the CD8α or CD8β chain could induce differential effects. We show here that two commonly used mAbs, against either the CD8α or CD8β subunit, can differentially affect cellular metabolism. Further, in vivo treatment leaves behind a population of CD8+ T cells with different phenotypic and functional attributes relative to each other or control CD8+ T cells. The impact of anti-CD8 antibodies on CD8+ T cell phenotype and function indicates the need to carefully consider the use of these, and possibly other "depleting" antibodies, as they could significantly complicate the interpretation of results or change the outcome of an experiment. These observations could impact how immunotherapy and modulation of CD8+ T cell activation is pursued.