Feline Leukemia Virus (FeLV)

Feline Leukemia Virus (FeLV) Antibody Products by Targets

FeLV particle. Fig.1 FeLV particle. (Hartmann & Hofmann-Lehmann, 2020)


Feline leukemia virus (FeLV) is a cancer-causing virus that infects and kills cats worldwide. It was discovered in 1964 in a group of cats suffering from lymphosarcoma. FeLV infection has been linked to a variety of diseases, including anemia, lymphoma, and immunosuppression. FeLV is spread between cats through infected saliva and urine. This virus affects not only domestic cats, but also wild cats, lynxes, jaguars, and other animals, but it cannot be transmitted to humans, dogs, or other animals. In recent years, vaccines have dramatically reduced the number of FeLV cases.

FeLV Structure

FeLV belongs to the family Retroviridae and the genus Gammaretrovirus. The spherical virion is 8-100 nm in diameter and has surface spikes of 8 nm. The FeLV genome is a single-stranded linear RNA that is approximately 8.4kb in length. The genome contains major structural and nonstructural genes such as gag, pol, and env, which are flanked by long terminal repeats (LTR). 5'-LTR controls transcription. The env gene codes for two proteins: the surface protein (SU; gp70) and the transmembrane protein (TM; p15E). The reverse transcriptase, protease, and integrase enzymes are all encoded by the pol gene. Gag encodes the capsid antigens p10, p15, and p27.

FeLV genome organization.Fig.2 FeLV genome organization. (Bolin & Levy, 2011)

FeLV Subtypes

FeLV has four major subtypes: A, B, C, and T. Each subtype enters cells via a different receptor. FeLV-A is ubiquitous and involved in all infections, whereas FeLV-B develops within a FeLV A-infected cat through recombination of FeLV A and endogenous FeLV. FeLV-B increases the risk of neoplastic diseases. FeLV-C is caused by env gene mutations, and FeLV-T has the ability to infect and destroy T lymphocytes, resulting in lymphoid depletion and immunodeficiency.


For many years, the presence of free p27 FeLV capsid antigen in blood, plasma, or serum has been the most commonly used marker of FeLV infection. The detection of p27 antigen using enzyme-linked immunosorbent assay (ELISA), immunochromatography (IC), and immunofluorescent antibody (IFA) has been used to identify cats with progressive FeLV infections. RT-PCR takes longer and costs more, but it is more sensitive because FeLV viral RNA in saliva and blood can be detected as early as one week after FeLV exposure.

Antibodies to FeLV

Creative Biolabs is your reliable partner with extensive experience in the fields of high-quality antibody production and engineering. With a focus on virology, we provide a variety of off-the-shelf viroantibody products to customers worldwide for veterinary immune research. We have anti-FeLV antibodies for a variety of hot targets (p27, gp70, p15E, etc.). We also provide antibody discovery, engineering, and customized services for specific FeLV antibodies. Please contact us to discuss your project.

To begin your research, browse our entire catalog of FeLV antibodies.


  1. Hartmann, K.; Hofmann-Lehmann, R. What's new in feline leukemia virus infection. Veterinary Clinics: Small Animal Practice. 2020, 50(5): 1013-1036.
  2. Bolin, L.L.; Levy, L.S. Viral determinants of FeLV infection and pathogenesis: lessons learned from analysis of a natural cohort. Viruses. 2011, 3(9): 1681-1698.
All products and services are intended for Research Use Only, and NOT to be used in diagnostic or therapeutic procedures.

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