Immune System

Innate immune response

Fill in the blanks with the correct term: adaptive, rapid, non-specific, mast, neutrophils, macrophages, histamine, highly specific, B Cells and T cells, antibodies, memory, white blood cells, and hemoglobin, serotonin.

1. Speed and Specificity: The innate immune response is _______________, often responding within minutes to hours after an infection. It is _______________, meaning it does not target specific pathogens but rather responds to a broad range of pathogens.
2. Components:
   • Physical and Chemical Barriers: Includes the skin, mucous membranes, sweat, sebum, and antimicrobial peptides.
   • Cells Involved: _______________, macrophages, dendritic cells, mast cells, basophils, eosinophils, and innate lymphoid cells.
   • Molecular Components: Cytokines, complement system proteins, and reactive oxygen species.
3. Mechanisms:
   • Phagocytosis: Neutrophils and _______________ engulf and destroy pathogens.
   • Inflammation: _______________ cells release _______________, causing vasodilation and increased capillary permeability.
   • Complement Activation: Enhances chemotaxis, opsonization, and formation of membrane attack complexes to lyse pathogens.
4. Lack of Memory: Traditionally, the innate immune response does not have significant memory capacity. However, there is a concept of “trained immunity” where previous exposure to certain pathogens can enhance the innate response to future infections.

Adaptive immune response

Fill in the blanks with the correct term: rapid, non-specific, mast, neutrophils, macrophages, histamine, highly specific, B Cells and T cells, antibodies, memory, white blood cells, and hemoglobin, serotonin.

1. Speed and Specificity: The adaptive immune response is slower, taking days to weeks to become fully effective. It is _______________, targeting specific antigens presented by pathogens.
2. Components:
   • Cells Involved: _______________ (including helper T cells and cytotoxic T cells).
   • Molecular Components: _______________ (IgM, IgG, IgA, IgE, IgD), cytokines, and major histocompatibility complex molecules.
3. Mechanisms:
   • Antibody Production: B cells differentiate into plasma cells that produce antibodies specific to the pathogen.
   • Cell-Mediated Immunity: T cells recognize and destroy infected cells. Helper T cells produce cytokines to activate other immune cells, while cytotoxic T cells directly kill infected cells.
   • Memory Cells: Both B cells and T cells generate _______________ cells that provide long-lasting immunity and a faster response upon re-exposure to the same pathogen.
   • Long-Term Memory: The adaptive immune response has a robust memory component, allowing for a quicker and more effective response to subsequent exposures to the same pathogen.

Pathophysiology of COVID-19 Infection

Fill in the blanks with the correct term: cytokines, K cells, innate, adaptive, B cells, T cells, cytokine storm, asymptomatic COVID.

COVID-19 is caused by the SARS-CoV-2 virus, which primarily targets the respiratory system. The virus binds to the ACE2 receptors on host cells, facilitating entry and replication. This leads to a cascade of immune responses, including the release of _______________ and activation of immune cells, which can result in inflammation and damage to lung tissue. Severe cases may progress to acute respiratory distress syndrome (ARDS), multi-organ failure, and death.

The immune response to SARS-CoV-2 involves both the innate and adaptive immune systems. Initially, the _______________ immune response is activated, with macrophages, neutrophils, and dendritic cells responding to the infection. This is followed by the _______________ immune response, where T cells and B cells are activated. _______________ help in killing infected cells, while _______________ produce antibodies that neutralize the virus. In some cases, an excessive immune response, known as a _______________, can occur, leading to severe inflammation, tissue damage, and potentially death.