Title : Immunotherapy with avian antibodies as a possible form of treatment of infections caused by Candida
Abstract:
The production, extraction, and use of antibodies from birds is an innovative methodology that supports several purposes, from passive immunotherapy to prophylaxis and diagnosis of diseases. Immunoglobulins Y (IgY), produced by chickens, are functionally similar to immunoglobulins G (IgG) from mammals. Antibodies can be extracted from egg yolks of laying hens, and it is not necessary to obtain them from the blood, as is performed with mammals. Therefore, the pain and suffering of animals are reduced.
It is important to note that the application of IgY in immunogenic therapy has several advantages over IgGs. The extraction and purification processes are relatively simple and inexpensive, and the cost of feeding and handling chickens is considerably less than that of mammals. Furthermore, avian immunoglobulins do not bind to mammalian antibody constant fraction receptors, do not activate the complement system or rheumatoid factor, and do not form immune complexes with IgGs. Therefore, its use is economical, viable, and ecologically correct, attracting researchers in the area.
Yeasts of the genus Candida are important pathological agents of mucosal and deep-tissue infections. Recently, a substantial increase in pathogenic fungi resistant to available antimicrobial agents was reported. In this context, immunotherapy with avian antibodies is a good option to overcome fungal resistance. In the literature, there are several reports on the potential therapeutic use of IgY to treat Candida infections. Most studies have focused on combating oral candidiasis caused by Candida albicans.
Immunotherapy using anti-C. albicans IgY has shown to have a protective effect in vivo against oral candidiasis in experimentally infected mice, in addition to reducing the dissemination of this yeast to the animals' internal organs. Furthermore, its protective efficacy has been demonstrated in humans, more specifically in elderly patients, in whom the use of an oral moisturizing gel containing anti-C. albicans IgY reduced for one month the number of C. albicans colony-forming units collected in swabs collected from the tongue of patients.
In most studies, to produce antibodies, animals were immunized with an inoculum of whole yeast cells. Despite this, immunoglobulin has also been produced against specific proteins of the fungus. For example, the high-affinity iron permease Ftr1 from C. albicans is a crucial membrane protein for the sequestration of iron from the host during an infection. Anti-Ftr1 IgY was produced and showed fungicidal activity, in addition to increasing the survival of G. mellonella larvae in an in vivo model of systemic infection.
Therefore, these studies support the development of drugs containing IgY anti-Candida antibodies, in the future, for the prevention and treatment of infections caused by these yeasts.
Audience take-away:
- The studies in therapeutic vaccine domain are conventionally performed for the treatment of cancer. Therefore, the audience will know a different branch of immunotherapy which is the use of antibodies for the treatment and prevention of fungal infections.
- Usually, the antibodies used in immunotherapy are extracted from the blood of mammals. The audience attending this lecture will learn about a different way of producing and extracting antibodies, which is based on the immunization of laying hens and the use of immunoglobulins from egg yolks. A methodology that prioritizes animal welfare.
- The lecture will provide ideas for researchers to develop projects in this field, still little explored.
