“Naturally, immunity is a natural physician that fends off all invading bacteria and viruses.” Ehsan Sehgal
Human body is like a perfectly working machine, with each organ as machine part performing its due role and action. Foreign pathogens such as bacteria, virus, pollutants act as enemies and manifest an infection or disease in our body.
The term immunity defines a complex and coherent biological system that can help tackle whatever belongs to the self, and to recognize and reject what is foreign (non-self). Our immune system is made up of multiple cellular systems, cytokines, growth factors and many secreted markers, that provide protection against foreign pathogens and keeps our body safe. The immune line acts as sentinels that imparts protection to our bodies and prevents any infection. In conditions like cancer, where immunity is compromised, the intention should be to activate the immune system to fight against the disease. This is termed as Immunostimulation. On the other hand, disease where hyperactivation of immune system is involved like Erythematosus lupus, Multiple sclerosis etc, the objective is to suppress the hyperactive immune system.
Inflammation is a part of innate immunity, that is first response to any foreign infection. This is characterized by rubor (redness), calor (heat), dalor (pain). Inflammation denotes exaggerated levels of immune activity. Ideally, there must exist a balance between the players of immunity and inflammation . A threshold level of cytokines and other factors is essential to maintain the homeostatic balance between anti and proinflammatory functions in the body. If this balance is disturbed, can result in uncontrolled secretion of inflammatory cytokines that can cause various disorders such as arthritis, psoriasis, organ inflammation, joint inflammation, neuronal inflammation etc. An inhibition of stimulated levels of cytokines reflects anti- inflammatory potential. Figure-1 shows the relevance of balanced immune system .
Preclinical screening of test agents for immunostimulatory/immunosuppressive or anti- inflammatory activity plays pivotal role in drug discovery and development. With the in vitro cell based screening, we can shortlist the active compounds to enter in vivo models. Also, the in vitro testing provides a deep insight into mechanistic action of test agent into immunity or inflammation.
At Dabur Research Foundation (DRF), we have an assorted collection of various immune cells, that can be used for screening immunostimulatory/immunosuppressive or anti- inflammatory activity, such as Dendritic cells (mouse bone marrow derived Dendritic cells), mouse splenocytes, Monocytes (human THP-1 cell line), Macrophages (mouse RAW264.7 cell line) . We have established, standardized and validated the screening models for immunomodulation as well as inflammation. Cells/cell lines are treated with Test agents at safe/non-cytotoxic concentrations and resultant modulation in cytokines/CD markers can be observed by ELISA/flow cytometry. Increase in phagocytosis or Natural killer cells activity is also observed that strengthens the immunity .
A modulation from the basal level reflects immunomodulation. However, when stimulated with an inflammatory stimulus such as LPS/any cytokine, the resultant effect of test agent reflects anti-inflammatory action. Other than model for systemic inflammation employing immune cell types, we also have a broad spectrum of specific models of inflammation for vital organs . The key to assays design remains the apt selection of target cell type, stimulation, and end points. For cytokine analysis, ELISA and multiplex arrays are used. A variety of cytokines including TNF, Interleukins etc. are included as end point markers. Table-1 shows the cell types involved in each inflammation model.
|Mouse splenocytes, BMDCs, THP-1, RAW264.7
The assay models can be customized with cell type/stimulants/End points as per the objective. At DRF we have screened more than 500 test agents for immunomodulatory and anti- inflammatory properties using the repertoire of assay models developed. This had helped vastly our partners in their drug discovery programs for immunity and inflammation. We are in the continuous process of developing new models for inflammation as per growing needs every day, that will further expand our existing repertoire of screening models.