Short Communication - Journal of Clinical Immunology Research (2023) Volume 6, Issue 3
Mechanisms of Immune Response to Infection: From Recognition to Defense
Department of Pediatrics, Cornell University Weill Medical College, New York, USA.
- Corresponding Author:
- Juan Alcocer
Department of Pediatrics
Weill Medical College, New York, USA
Received: 02-Jul-2023, Manuscript No. AACIR-23-104161; Editor assigned: 04-Jul-2023, Pre QC No. AACIR-23-104161(PQ); Reviewed: 18-Jul-2023, QC No. AACIR-23-104161; Revised: 21-Jul-2023, Manuscript No. AACIR-23-104161 (R); Published: 25-Jul-2023, DOI:10.35841/aacir-6.3.147
Citation: Alcocer J. Mechanisms of immune response to infection: From recognition to defense. J Clin Immunol. 2023;6(3):147
The immune system plays a crucial role in defending the body against infectious agents. When pathogens such as bacteria, viruses, or parasites invade the body, the immune system mounts a coordinated response to eliminate the threat. This essay aims to explore the mechanisms of immune response to infection, focusing on the innate and adaptive immune responses. By understanding these mechanisms, we can gain insights into the complex interactions between pathogens and the immune system, leading to the development of targeted therapies and interventions .
Prognostic estimates can be extremely accurate when used on large statistical populations; for instance, it is possible to say with some confidence that "45% of patients with severe septic shock will die within 28 days" because prior studies have shown that this percentage of patients did indeed pass away. Because patient-specific factors can significantly alter the expected course of the disease, this statistical information does not apply to the prognosis for each individual patient. Additional information is required to determine whether a patient belongs to the 45% who will die or the 55% who will survive .
Innate immune response
The innate immune response serves as the first line of defense against infections. It is a rapid and nonspecific response that provides immediate protection. Key components of the innate immune system include physical barriers, such as the skin and mucous membranes, as well as cellular and molecular components
Physical barriers: Physical barriers prevent pathogens from entering the body. The skin acts as a physical barrier, while mucous membranes in the respiratory, gastrointestinal, and urogenital tracts secrete mucus that traps pathogens .
Cellular components: Cells of the innate immune system include phagocytes, Natural Killer (NK) cells, and dendritic cells. Phagocytes, including neutrophils and macrophages, engulf and destroy pathogens. NK cells recognize infected or abnormal cells and induce their death. Dendritic cells capture antigens and present them to the adaptive immune system.
Molecular components: The innate immune system produces various molecules that enhance the immune response. These include cytokines, which mediate communication between cells, and complement proteins, which opsonize pathogens for phagocytosis or directly lyse them.
Inflammatory response: Inflammation is a hallmark of the innate immune response. It is triggered by the release of proinflammatory cytokines and chemokines, leading to increased blood flow, recruitment of immune cells, and activation of phagocytes at the site of infection .
Adaptive immune response
The adaptive immune response is a highly specific and tailored response that develops after exposure to pathogens. It involves the activation of lymphocytes, specifically T cells and B cells, which work together to eliminate the infection and establish immunological memory.
Antigen recognition: T cells and B cells recognize specific antigens presented by antigen-presenting cells, primarily dendritic cells. T cells recognize antigens presented on Major Histocompatibility Complex (MHC) molecules, leading to T cell activation. B cells recognize antigens directly, leading to B cell activation.
T cell response: Once activated, T cells differentiate into effector T cells with distinct functions. Cytotoxic T cells directly kill infected cells, while helper T cells secrete cytokines that enhance immune responses. Regulatory T cells help maintain immune tolerance and prevent excessive immune reactions .
B cell response: Activated B cells differentiate into plasma cells that produce and release antibodies. Antibodies bind to specific antigens, neutralizing pathogens or marking them for destruction by other components of the immune system.
Immunological memory: Following clearance of the infection, a pool of memory T cells and memory B cells is established. This enables a faster and more effective response upon subsequent encounters with the same pathogen, providing long-term protection.
Interaction between innate and adaptive immune responses
The innate and adaptive immune responses are interconnected and collaborate to combat infections.
Antigen presentation: Dendritic cells link the innate and adaptive immune responses by capturing antigens at the site of infection and presenting them to T cells, initiating the adaptive immune response.
Cytokine signaling: Cytokines produced during the innate immune response shape the subsequent adaptive immune response. For instance, cytokines released during inflammation help.
- Bermudez-Morales VH, Gutiérrez LX, Alcocer-González JM, et al. Correlation between IL-10 gene expression and HPV infection in cervical cancer: a mechanism for immune response escape. Cancer Invest. 2008;26(10):1037-43.
- Cunningham-Rundles S, McNeeley DF, Moon A. Mechanisms of nutrient modulation of the immune response. J Allergy Clin Immunol. 2005;115(6):1119-28.
- Zhang Q, Cao X. Epigenetic regulation of the innate immune response to infection. Nat Rev Immunol. 2019;19(7):417-32.
- Mittrücker HW, Kaufmann SH. Immune response to infection with Salmonella typhimurium in mice. J Leukoc Biol. 2000;67(4):457-63.
- Machado PR, Araújo MI, Carvalho L, et al. Immune response mechanisms to infections. An Bras Dermatol. 2004;647-62.