Promising Treatment for FeLV & FIV

Lymphocyte T-cell immunomodulator (LTCI) is a novel and commercially available immunotherapeutic agent. It is marketed as an adjunct therapeutic aid for cats infected with feline leukemia (FeLV) and feline immunodeficiency viruses (FIV) and may help alleviate many FeLV- and FIV-induced clinical and laboratory abnormalities. LTCI is a crude thymic glycoprotein produced by a thymic stromal epithelial line. It activates T-helper CD4+ T cells to produce interleukin-2 (IL-2), gamma interferon (IFN), and other cytokines. IL-2 and gamma IFN stimulate CD8+ cytotoxic T lymphocytes to attack virus-infected cells as well as tumor cells. The therapeutic effects of LTCI are therefore a result of this cycle. Several in vivo and in vitro studies in murine, canine, and feline models confirmed the utility of LTCI as an immunomodulator in viral infections, and identified increased efficacy of immune responses to infection and tumors, decreased circulating viremia, and improved laboratory measures. Results were similar in an experimentally induced FIV model and in naturally infected FeLV and FIV field cases. These data collectively suggest that administration of LTCI should result in cytokine production and activation of cellular-protective processes. Clinical trials in feline populations are planned and should yield much more information.

COMMENTARY: Immunotherapeutic agents are substances that modulate the immune system to achieve a therapeutic goal and, in veterinary medicine, are regulated by the U.S. Department of Agriculture (USDA) Center for Veterinary Biologics. LTCI has been granted a conditional license as an aid in the treatment of cats infected with FeLV or FIV. Conditional licenses are granted by the USDA to products that have met reasonable expectation of efficacy, have demonstrated purity, and have passed safety testing. This is a promising treatment for cats infected with these viruses.

Lymphocyte T-cell immunomodulator (LTCI): Review of the immunopharmacology of a new veterinary biologic. Gingerich DA. INTL J APPL RES VET MED 6:61-68, 2008.