Specialists at the Institute of Biomedical Research of the National Autonomous University of Mexico (UNAM) are working on developing a vaccine for HIV/AIDS and for cancer.
The team of researchers is searching for an HIV vaccine that can induce humoral and cell-mediated immune responses, since these mechanisms are fundamental in the defense against pathogens.
To face the challenge of antigenic variation of the virus, the researchers suggest that the construction of vaccines based on Variable epitope libraries (VELs) can counteract this obstacle. Epitopes are small fragments of an antigen – e.g. a protein – recognized by the immune system.
Dr. Karen Manoutcharían, head of research, explains that for treating antigenically variable pathogens, they need to build an equally complex immunogen as the target itself, incorporating antigenic variability.
VELs will allow facing the enormous variability of pathogens such as HIV, hepatitis, influenza, malaria, dengue and cancer. The research team proposal “is a new concept of vaccines that can incorporate antigenic diversity in a vaccine,” the UNAM scientist said.
Manoutcharían said that conventional vaccines are based on total antigen, but its application to antigenically variable pathogens is unsuccessful, since the high antigenic variability allows them to escape from recognition by the immune system.
Applying this new concept allowed to build vaccines capable of inducing broadly neutralizing sera against HIV in mice. Neutralization by sera is the best in its class compared to other epitopes-based vaccines.
Using the same VELs concept, the team created vaccines against breast cancer and melanoma. When VELs-based vaccines were applied on breast cancer mouse models, tumor growth and lung metastasis mediated by the activation of lymphocytes-T were reduced.
The main problem of cancer vaccines is the high antigenic variability of cancer cells mediated by mutations appearing as a result of genetic instability. An additional problem is the inability to break immune tolerance against their own proteins (antigens), as these cancerous cells present antigenic profile almost identical to the profiles of healthy cells in the same individual.
The results using VELs concept are highly promising as a replicable method for generating vaccines against antigenically variable pathogens and cancer.
The findings were published in the journals Molecular Immunology, Vaccine and Human Vaccines and Immunotherapeutics.
Source: Invdes
