Infektsioonivastus

Infektsioonivastus, also known as the immune response to infection, is the complex series of reactions undertaken by an organism's immune system to defend against pathogenic microorganisms such as bacteria, viruses, fungi, and parasites. This response is a critical component of maintaining health and survival, preventing or limiting the damage caused by invading pathogens.

The infection response can be broadly divided into two main branches: the innate immune response and the adaptive immune response. The innate immune response is the body's first line of defense, acting rapidly and without prior exposure to the specific pathogen. It involves physical barriers like skin and mucous membranes, as well as cellular components such as phagocytes (like macrophages and neutrophils) that engulf and destroy pathogens, and natural killer cells that target infected cells. Inflammation, characterized by redness, swelling, heat, and pain, is a hallmark of the innate response, facilitating the recruitment of immune cells to the site of infection.

If the innate immune response is insufficient to clear the infection, the adaptive immune response is activated. This response is slower to develop but is highly specific and can generate immunological memory, meaning the body can mount a faster and more robust response upon subsequent encounters with the same pathogen. Key players in the adaptive immune response include lymphocytes, specifically B cells that produce antibodies to neutralize pathogens and T cells that directly kill infected cells or help regulate the immune response. Antibodies can mark pathogens for destruction, block their entry into cells, or neutralize their toxins.

The interplay between the innate and adaptive immune systems is crucial. Components of the innate immune system help to initiate and shape the adaptive immune response, while the adaptive immune system provides targeted and long-lasting protection. A successful infection response leads to pathogen clearance and resolution of inflammation, while a dysregulated or insufficient response can result in chronic infection, tissue damage, or systemic illness.