Virulence Chart

ENZYMES AND EXOTOXINS

Overview of Key Terms

  • Enzymes: Biological catalysts that accelerate chemical reactions.

  • Exotoxins: Toxic substances secreted by bacteria that can lead to various diseases.

  • Adhesins: Molecules that facilitate adherence of pathogens to host cells.

Detailed Breakdown of Specific Organisms and Their Actions

Neisseria gonorrhoeae

  • Factor: Pili (G-)

  • Disease: Gonorrhea (sexually transmitted)

  • Action: Adheres to endocervical columnar epithelial cells, specifically in the cervix of females only.

Streptococcus mutans

  • Factor: Glycocalyx (slime layer)

  • Disease: Dental caries (most common infectious disease)

  • Action: Provides a means for the organism to bind to tooth surfaces, thereby forming a biofilm.

Bacillus anthracis

  • Factor: Lethal Factor

  • Disease: Anthrax (cutaneous or respiratory)

  • Action: Causes the death of macrophages.

Clostridium tetani

  • Factor: Tetanospasmin neurotoxin

  • Disease: Tetanus

  • Action: Blocks inhibitory neurotransmitters, leading to spastic paralysis.

Staphylococcus aureus

  • Factor: TSST-1 (Toxic Shock Syndrome Toxin - 1)

  • Disease: Toxic Shock Syndrome

  • Action: Acts as a super antigen, eliciting systemic shock which can result in acute peripheral circulatory failure.

Yersinia pestis

  • Factor: Not specifically listed

  • Disease: Bubonic plague/Pneumonic Plague

  • Action: Activation of fibrinogen to fibrin clot formation around bacteria, leading to antiphagocytic activity.

Haemophilus influenzae

  • Factor: Capsule

  • Disease: Mainly affects children, causing infant meningitis (6 months to 2 years; critical period where mother's antibodies are absent and the child's immune system is still developing).

  • Action: Antiphagocytic properties impair the ability of leukocytes to phagocytize the organism.

IMMUNE SYSTEM CELLS

Overview of Immune Cells

  • Erythrocytes: Red blood cells (RBC) derived from bone marrow.

  • Basophils: Part of the innate immune response.

  • Eosinophils: A type of white blood cell, part of the innate immune response.

  • Myeloid Macrophages: Derived from myeloid progenitors, important in both innate immunity and tissue repair.

Stem Cells

  • Type: Hematopoietic stem cells in the bone marrow.

  • Derivation: Give rise to various blood cells including platelets, neutrophils, macrophages, etc.

Lymphoid Precursors

  • T cells: Mature in the thymus, involved in cell-mediated immune response.

  • B cells: Mature in bone marrow and serve as antibody factories in the humoral immune response.

Polymorphonuclear Cells (PMNs)

  • Definition: Neutrophils, which are first responders to sites of infection.

  • Role: Attracted to sites by bacterial proteins, playing a crucial role in the innate immune response.

IMMUNOGLOBULINS AND ANTIBODY STRUCTURE

Antibody Structure

  • Epitope Binding: Region of antibodies that binds to specific antigens.

  • Heavy Chain: The larger polypeptide chain part of the antibody, providing structural integrity.

    • Constant Region (C): Amino acid sequence that is the same across all members of the same antibody class.

    • Variable Regions (V): Differences in amino acid sequences allowing for specificity against different antigens.

Activation and Function

  • B Cell Receptors (BCR): Similar to antibodies, the BCR has identical epitope binding sites as antibodies secreted by the B cell.

  • Local Immune Response: When an antibody is bound, it stimulates the local immune cells to respond to the threat.

Summary

  • Immune Cells: Distributed and activated differently depending on their roles in innate versus adaptive immunity, highlighting the complexity and specialization of the immune response.