Body's defences
- Innate
- Skin
- Complement
- Interactive
- Cellular
- Antibody
Immunisation
- Active or Passive
- Active: pre-formed antibodies (HBsAG, immunocompromised patients with shingles, botulism, rabies)
- Passive: transplacental transfer of IgG protects for first 6 months of life
- Natural or artificial
- Natural: following infection
- Following vaccination
Different types of vaccinations
- Live attenuated: - BCG, sabine for polio, MMR
- Long lasting immunity
- Potentially dangerous in immunocompromised patients
- Killed organisms: typhoid, cholera, pertussis
- Smaller immune response: usually boosters are required
- Toxoid
- Not the infection but the effects of toxin that result from infection (eg. Tetanus toxoid)
- Other bacterial constiuents
- Surface polysaccharides and proteins
Immunoglobulin
- Antigen binding sites (light and heavy chain regions)
- Complement activation parts
- Immune adherence
- Heavy chains determine the class of immunoglobulin - GAMDE
- Light chains are kappa- or lambda- irrespective of the immunoglobulin class
- IgG: most important Monomeric: activates complement, binds to killer t-cells
- IgA: present in secretions of BIT, respiratory tract; Dimer with J-chain
- IgM: Largest - Pentamer
- IgE: Monomer bound to mast cells
Immunodeficiency
- Acquired
- Drugs
- Infections
- Congenital
- Bruton's X-linked gammopathy
- T-cells: Thymic atrophy in Di-George anomaly
- SCID
- Lymphoma
Infections in Compromised patients
- Congenital
- Bruton type hypogammaglobulinaemia
- Di George type
- Combined
- Deficiency of neutrophil function in chronic granulomatous disease
- Acquired
- Infections: AIDS
- Drugs: steroids, cytotoxics
- Diabetes (also because glucose as a culture medium in urine and on skin)
- Instrumentation - lines, catheters, ventilation
- Prosthesis: hips, knees, heart valves
Sources of infection
- Endogenous
- Colonic bacteria
- GIT
- Skin
- Exogenous
- Foamites
- Other people
- Transplanted tissues
- "Opportunist"