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The Corona virus disease, 2019 (COVID-19) pandemic is a worldwide public health crisis with over 153 million confirmed cases and 3.2 million deaths as of April 2021. COVID-19 is caused by a novel coronavirus called SARS-CoV-2. SARS-COV-2 infects hosts via its spike (S) protein, which has two portions, S1 that binds the cell and S2 that is involved in viral entry via fusion with the cell membrane. There are several vaccines available for COVID-19 patients that directly target SARS-CoV-2 by systemic immunization.

Human immunodeficiency virus (HIV) infections remain a pandemic, most prevalent in Africa and the Americas. Anti-retroviral treatments have been effective in preventing spread of the virus and active outbreaks of acquired immune deficiency syndrome (AIDS). However, the development and deployment of an effective vaccine would provide long-lasting protection and alleviate the need to depend heavily on prevention methods that require continued access and adherence.

Vaccines against non-viral cancers target mainly differentiation antigens, cancer testis antigens, and overexpressed antigens.  One common feature to these antigens is their presence in central immunological tolerance. Using these vaccines, T cells underwent depletion of high avidity clones directed against such antigens. This depletion can cause the loss of T cells bearing high affinity T cell receptors (TCRs) for their cognate antigens which have superior cytotoxic capacity, longer persistence in the tumor microenvironment, and decreased susceptibility to immune suppression.

The development of an effective HIV vaccine has been an ongoing area of research. High variability in HIV-1 virus strains, however,  represents a major challenge.  Ideally, an effective candidate vaccine would provide protection against the majority of clades of HIV.  Two major hurdles to overcome are immunodominance and sequence diversity. Researchers at the National Cancer Institute (NCI) have developed a vaccine that overcomes these major hurdles by utilizing a strategy that identifies conserved regions of the virus and exploits them for use in a targeted therapy.

The development of more targeted means of treating cancer is vital. One option for a targeted treatment is the creation of a vaccine that induces an immune response only against cancer cells. In this sense, vaccination involves the introduction of a peptide into a patient that causes the formation of antibodies or T cells that recognize the peptide. If the peptide is from a protein found selectively on/in cancer cells, those antibodies or T cells can trigger the death of those cancer cells without harming non-cancer cells. This can result in fewer side effects for the patient.

Tumor invasion and metastasis are the primary drivers of cancer-related mortality. Therapies that have an ability to specifically target invasive and/or metastatic cells are anticipated to have a significant impact in the clinical management of advanced cancers.

The development of an effective HIV vaccine has been an ongoing area of research. The high variability in HIV-1 virus strains has represented a major challenge in successful development.  Ideally, an effective candidate vaccine would provide protection against the majority of clades of HIV.  Two major hurdles to overcome are immunodominance and sequence diversity.  This vaccine utilizes a strategy for overcoming these two issues by identifying the conserved regions of the virus and exploiting them for use in a targeted therapy. 

The manner by which cancers evade the immune response is not well-understood. What is known is that the manner is an active process that regulates immune responses employing at least two types of suppressive cells, myeloid-derived suppressive cells and regulatory T cells (Tregs), a key subset of CD4+ T cells that controls peripheral tolerance to self- and allo-antigens. Tregs are considered to play a key role in the escape of cancer cells from anti-tumor effector T cells.

Current influenza vaccines mainly induce antibodies against the surface glycoprotein hemagglutinin (HA) that block viral attachment to its host receptors and viral membrane fusion to the host cell. The immunodominant head region of HA undergoes antigenic drift and antibodies directed to the head confer little cross-protections between strains or subtypes.