Immunotherapy research uses cell lines as much as every other branch of microbiology. For example, the T2 cell line is lacking in a peptide transport protein ca

Immunotherapy research uses cell lines as much as every other branch of microbiology. For example, the T2 cell line is lacking in a peptide transport protein called TAP, which makes it handy for studying the immune recognition of arbitrary peptides (not just those from the cell). * Examining the presentation of tumor-associated antigens on peptide-pulsed T2 cells (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3894244/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3894244/) And if you want to study the effectiveness of any immunotherapy, it's very common to implant a mouse cell line like B16 in live mice and then see if the tumor regresses under different treatment conditions (e.g. with or without checkpoint blockade). Example: * Localized Oncolytic Virotherapy Overcomes Systemic Tumor Resistance to Immune Checkpoint Blockade Immunotherapy (http://stm.sciencemag.org/content/6/226/226ra32.short http://stm.sciencemag.org/content/6/226/226ra32.short) ...but really every preclinical paper on a new kind of vaccine or immunomodulatory antibody uses cancer cell lines in this way.