Positive and Negative Selection of T Cells

Adaptive immune cells, like T cells, play a critical role in protecting our bodies against invading pathogens, a task that relies upon their ability to recognize pathogens as foreign, or ‘non-self’. This begs the question, though, of how adaptive immune cells distinguish between self and non-self. How is it that T cells know to attack … Continue reading Positive and Negative Selection of T Cells

How-to make: a T cell receptor (the simpler version)

T cell receptors are required for the activation, regulation, and function of T cells. TCRs are generated by the random joining of gene segments in the TCR gene loci. TCR assembly occurs through a process called V(D)J recombination, so named for the gene segments joined to make the β–chain of the TCR and the heavy … Continue reading How-to make: a T cell receptor (the simpler version)

The Mighty, Mighty Microbiome

The microbiome is a group of microorganisms living in a particular environment (for example, the human gut).  These microorganisms are not just limited to bacteria: viruses, fungi, and archaea can also be present. Microbiomes are not limited to humans or even to mammals--insects and plants have microbiomes that are crucial for their health.  Microbiomes are … Continue reading The Mighty, Mighty Microbiome

Regulating “self” versus “non-self” – T cell tolerance mechanisms

 Central Tolerance Central tolerance refers to the negative selection step in T cell differentiation. It occurs in the thymus, where newly recombined T cell receptors are screened against a bevy of self-antigens and overactive clones are deleted. See Positive and Negative Selection of T Cells. Clonal Deletion - T cells that recombine a TCR with a … Continue reading Regulating “self” versus “non-self” – T cell tolerance mechanisms

Friendly Fire – an introduction to autoimmune disease

 Autoimmunity is a blanket term describing pathologies where the immune system attacks its host body. The typical paradigm is that the immune system protects us from foreign invaders- pathogens looking for a niche to colonize. In autoimmune disease, the immune system mistakes our body’s tissues for a target- and harms them. Whether due to a … Continue reading Friendly Fire – an introduction to autoimmune disease

Neutralizing your enemies by eating them?  Just an ordinary day in the life of the immune system!

Phagocytosis is the process of a cell ingesting another cell or particle.  It works by having the phagocytosing cell bind the desired target onto its surface and bringing it inward while it engulfs the target.  This is a relatively simple mechanism that cells such as macrophages of the immune system can use to destroy foreign … Continue reading Neutralizing your enemies by eating them?  Just an ordinary day in the life of the immune system!

Vector-borne diseases: directions in transmission

Pathogens, including viruses and bacteria, have one primary goal: reproduction. Transmission is the movement of a pathogen from one host to the next. Infectious pathogens that cause disease have evolved to enhance the likelihood of transmission so that they can infect more hosts. For example, influenza virus and the measles virus are both highly contagious … Continue reading Vector-borne diseases: directions in transmission