Nude mice immunity

[julyfrombrest]

I work on tumors induced in Nude mice by subcutaneous injection of a cell line established from a gastric adenocarcinoma of a woman, 60 years (HGT-1 line, if it means something to somebody …). The problem stems from our results in Immunohistochemistry: our primary antibodies target human antigens and have been produced in mice, so we use an anti-mouse secondary antibody. On negative control slides (on frozen tissue, primary antibody replaced by PBS), the background noise is huge, and mainly affects blood microvessels (hence murine tissue), even by blocking endogenous peroxydases, or mouse Ig … .. Ig that should not be present in Nude mice? No?

If anyone knows more about the immunity of these mice, or has had such worries, could he help me? Thanks in advance