Immune Response Activation

**3**

**Chapter 1**

*Rajeev K. Tyagi*

**1. Introduction**

Introductory Chapter: Immunity

The mammalian immune system is comprised of two branches of immune system; innate and adaptive, which render tolerance towards host for protection from microbial infections. The innate immune system consists of functionally distinct mechanism that evolved to render protection against pathogens. The nonadaptive immune system senses pathogens through pattern recognition receptors which trigger the activation of antimicrobial defense system to stimulate and provoke the efficient immune response. The acquired immune system in response activates the nonadaptive immune effector mechanisms in an antigen-specific and dependent manner. Although the link between various immune components are not fully understood, recent progresses bring us closer to an integrated view of immune

The infectious diseases are the leading cause for the greater rate of morbidity and

The innate immune system is the phylogenically oldest component of the human

immune system. The innate immune system is highly complex and consists of barriers to infection (epithelia of skin, gastrointestinal, respiratory, genitourinary tracts), antimicrobial peptides and proteins, humoral components (i.e., complement and opsonins) and cellular components (i.e., neutrophils, monocytes/macrophages, dendritic cells, and innate lymphoid cells). Innate immunity serves as the front line of host defense and plays an essential role in preventing infection while tolerating normal host flora. The defects in innate immunity are associated with invasive, life-threatening infection, and inappropriate activation of innate immune system may lead to auto-inflammatory states. The innate immune system directs the

The human acquired immune system is responsible for the destruction of foreign particles once they have entered the body. During the first exposure to an invader (which could be a virus, a bacteria or any unwanted particle), the acquired immune system must "learn" how to attack and destroy the foreign particle. This

mortality world-wide and are a major challenge for the biomedical sciences. The physical methods such as improved sanitary conditions, clean water supplies and vector control are by far the most effective measures, development of vaccines and therapeutics are panacea for their treatment. The development of vaccine and therapeutic interventions require the understanding of host immune system. Recently, significant progress has been made towards unraveling the mechanisms of microbial pathogenesis and host-microbe symbiosis. There are many challenges remain and most daunting is the development of effective vaccine. Indeed, it is not known how to elicit protective immunity against most pathogens in a safe and practical manner. To address and overcome the autoimmune response mounted by the host are

and Immunomodulation

system and its function towards the host defense [1].

required and to be explored by the basic science researchers.

subsequent development of adaptive immune responses [2].
