NK Cells Shed Important New Light to Cancer Vaccine Development

There exist numerous sufferings resulted from miscellaneous diseases on the long march of human history. Threatened by these horrible illnesses, few people could fight back and survive until the emergence of vaccines.

Vaccine refers to a biological product intended to prevent diseases induced by bacteria, viruses, tumor cells, etc., which enable the body to produce specific immunity and make the recipient obtain immunity through vaccination. Through years of development of modern medicine, nowadays ordinary people have access to the vaccination various diseases from the moment of the birth, such as chickenpox, hepatitis B, tuberculosis, etc.

These diseases, which used to have a high mortality rate, have become no longer dreadful owing to the appearance of the vaccine. However, what dreaded at present are no longer these diseases, but a more incurable disease "cancer", which poses a giant challenge for the cancer vaccine development.

Vaccine is an auto-immune preparation for preventing infectious diseases, made of pathogenic microorganisms and/or their metabolites through artificial attenuation, inactivation or genetic modification, which retains the ability of the pathogen to stimulate the animal's immune system. Then, the immune system can follow the original memory produced at the vaccination to produce certain protective substances when attacked by the corresponding pathogen. Similarly, tumor vaccines kill tumors by recognizing tumor specific antigen or tumor-associated antigen tumor associated antigen to activate antigen-presenting cells and induce antigen-specific immune responses. The novel cancer vaccine development aims to find a new target to replace tumor cells, which can trigger immune responses and memories without causing cancer.

So as to develop a qualified cancer vaccine that may bring new hope for abundant patients, countless researchers and industrial companies have engaged in this field. A recent study published in Proceedings of the National Academy of Sciences reported that natural killer cells (NK cells) probably are the key to developing potential cancer vaccines. As a type of white blood cell belonging to the innate immune system, NK cells can patrol the body to find harmful cells, such as cancer cells or viral infections, but they cannot effectively memory these harmful cells.

Scientists have long known that T cells and B cells can empower the body's immune system long-term memory. In this study, researchers tried to determine how NK cells trigger immune memory in the absence of T cells or B cells, likely opening a whole new field of immunological research. NK cells use specific receptors to decide whether a cell faces a threat, and Ly49 may be involved. A specific protein is used to vaccinate mice that have been depleted of T cells or B cells, the receptor of which can recognize foreign threats. When inoculated mice are exposed to melanoma cells that express the same protein, the self-protective mechanisms can prevent mice from cancer.

When the researchers repeated the experiment in mice lacking the Ly49 protein, they found no protective mechanism against cancer in mice. Now researchers can successfully immunize mice that lack both T and B cells to help protect them against cancer, perhaps because of the Ly49 receptor.

Although there is no final conclusion on NK cells’ function to develop cancer vaccines, the results suggest that vaccination of mice without T and B cells may be effective against cancer, which may inspire some researchers or industrial companies to adjust their research projects on vaccine development services for a long-anticipated success.