Small and Large Intestines Possess Different Immune Systems

Effect of commensal bacteria

In this article, I briefly explain the disparity in immunity in the small and large intestines. Distinct Immunity in Small and Large Intestine The small and large intestines manage their relationship with the microbiome by sharing general strategies. However, the physiology of each section is distinct, as are the microbial communities and immune cells that … Read more >>

Negative regulation of B-cell activation

In this article, I briefly describe the negative regulation of B-cell activation. B-cell activation and control Presentation of antigens via MHC and receiving co-stimulatory signals (CD40-CD40L) from TH2 cells, results in the activation of B cells (figure 1). Following activation, B cells undergo cycles of mutation and selection to produce high-affinity memory B cells and … Read more >>

The absence of a costimulatory signal leads to clonal anergy

In this article, I briefly explain clonal anergy and its relation with a costimulatory signal. Clonal anergy A state of clonal anergy develops, when a naïve T cell engages its TCR with an antigen presented by an MHC, without a suitable costimulatory signal. It is a state, where the specific T cell clone shows no … Read more >>

The coinhibitory receptors: CTLA-4, PD-1, and BTLA

In this article, I briefly describe the working of the coinhibitory receptors CTLA-4, PD-1, and BTLA. Coinhibitory receptor Costimulatory and coinhibitory receptor molecules are vital in regulating immune responses to infections. Coinhibitory receptors bind with their ligands and suppress excess immune responses. When T cells get infected, they tend to express coinhibitory receptors and acquire … Read more >>

Costimulatory receptors for activation of T cells

In this article, I briefly describe costimulatory receptors CD28 and ICOS and how they bind with their ligands. Costimulatory receptors Co-stimulatory signals are required for optimal T-cell activation. T-cell non-responsiveness arises from high affinity TCR-MHC interactions in the absence of functional antigen presenting cells (APCs). It is called T cell anergy. The interaction between specific … Read more >>

Antigen-antibody interaction- Complement fixation

In this article, I briefly describe complement fixation, which is an antigen-antibody interaction. Antigen-antibody interaction The antigen-antibody interaction is a bimolecular association. This does not lead to an irreversible chemical alteration in either the antibody or the antigen. This association involves many non-covalent interactions between the antigenic determinant (epitope) of the antigen and the variable-region … Read more >>

The Antigen-Antibody Interaction- Immunofluorescence

Direct and indirect methods of immunoflorescence

In this article, I briefly describe the method of immunofluorescence, which is an antigen-antibody interaction. Antigen-Antibody Interaction The Interaction between antigen and antibody is a bimolecular association, which does not lead to an irreversible chemical alteration in either the antibody or the antigen. The antigen-antibody association involves many non-covalent interactions between the antigenic determinant (epitope) … Read more >>

Type-III Hypersensitivity

In this article, I briefly explain type-III hypersensitivity along with its effects. Hypersensitivity Hypersensitive reactions are the inflammatory reactions within the humoral or cell-mediated branches of the immune system. These reactions cause extensive tissue damage, or occasionally death. The reactions are immediate or may be delayed type depending on the symptoms. In 1963, P.G.H. Gell … Read more >>

The antigen-antibody interaction- Radioimmunoassay

In this article, I briefly describe the radioimmunoassay, which is a process of antigen-antibody interaction. Antigen-antibody interaction The Interaction between antigen and antibody is a bimolecular association, which does not lead to an irreversible chemical alteration in either the antibody or the antigen. The antigen-antibody association involves many non-covalent interactions between the antigenic determinant (epitope) … Read more >>

The antigen-antibody interaction- Enzyme-linked Immunosorbent Assay (ELISA)

In this article, I briefly describe the enzyme-linked immunosorbent assay, which is an antigen-antibody interaction. Antigen-antibody interaction The Interaction between antigen and antibody is a bimolecular association, which does not lead to an irreversible chemical alteration in either the antibody or the antigen. The antigen-antibody association involves many non-covalent interactions between the antigenic determinant (epitope) … Read more >>