Sebaceous glands secrete sebum which has antibacterial properties. Moreover, sweat washes infections off as the high salt content of sweat dries micro-organisms off. Tears and saliva are secretions that wash the cornea and mouth continuously. Many epithelial surfaces in the body contain cilia. These cilia beat rhythmically to transport matter out of the body respiratory epithelium. Saliva contains anti-bacterial properties due to lysozymes. Some epithelia produce mucus which also acts as a barrier against infections.
If and when micro-organisms penetrate these defense systems they meet the lymphocytes , macrophages which phagocytose foreign matter non-specifically. This may or may not lead to the generation of a specific immune response. When a foreign substance is phagocytozed by a macrophage, a white blood cell, or an antigen presenting cell, it gets processed inside the host cell.
There are antigen binding receptors called major histocompatibility complexes MHC type 1 and 2. There is an enormous variation among antigen receptors in both T cells and B cells. CD4 T Lymphocytes get activated by this receptor cross-linkage, and they produce cytokines which promote proliferation of selected lymphocytes, the formation of new lymphocytes with selected receptor types, and activation of B cells to form antibodies.
These mechanisms culminate in the destruction of the foreign organisms phagocytozed previously. Thank you for participating in this module. Click below to download the certificate.
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Account Information. Welcome to Learn Immuno-Oncology. Mechanisms of inflammation and tissue repair. Goldman-Cecil Medicine. Philadelphia, PA: Elsevier; chap Tuano KS, Chinen J. Adaptive immunity. Philadelphia, PA: Elsevier; chap 2. Updated by: Stuart I.
Editorial team. Immune response. Examples of innate immunity include: Cough reflex Enzymes in tears and skin oils Mucus, which traps bacteria and small particles Skin Stomach acid Innate immunity also comes in a protein chemical form, called innate humoral immunity. Lymphocytes are a type of white blood cell. There are B and T type lymphocytes. B lymphocytes become cells that produce antibodies.
Antibodies attach to a specific antigen and make it easier for the immune cells to destroy the antigen. T lymphocytes attack antigens directly and help control the immune response. They also release chemicals, known as cytokines, which control the entire immune response. Watch this video about: Immune response. Watch this video about: Phagocytosis. Watch this video about: Vaccines. Alternative Names.
Second line defense is shown in figure 2. Figure 2: Second Line Defense. The second line defense is the nonspecific immune response, which is initiated by the entry of a pathogen into a tissue. Cells such as macrophages , natural killer cells , monocytes , neutrophils , mast cells, and dendritic cells serve as phagocytes , which destroy the pathogens inside tissues. Inflammation, fever, histamines, and complement proteins are the nonspecific immune responses of the second line defense of the body.
Specific Immune Response: Specific immune response is the immune response against a specific antigen. Nonspecific Immune Response: Nonspecific immune response is the immediate protective response of the immune system that does not require previous exposure to the antigen.
Specific Immune Response: Specific immune response belongs to adaptive immunity. Nonspecific Immune Response: Nonspecific immune response belongs to innate immunity. Specific Immune Response: Specific immune response is the third line defense of the body. Nonspecific Immune Response: Nonspecific immune response can be either first line or second line defense of the body.
Specific Immune Response: Specific immune response is the supreme immune response of the body against a particular pathogen. Nonspecific Immune Response: Nonspecific immune response is the fundamental immune response of the body against pathogens.
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