Johnson Flashcards
How does the body recognize a viral infection?
- toll-like receptors recognize viral ds RNA and activate innate immunity
How does interferon induce a cell to an antiviral state?
- INF alpha and beta release activates dendritic cells, macrophages, NK cells and T and B cells
- protein kinase R production - blocks viral synthesis and causes apoptosis
- 2’5’-oligoadenylate synthetase produciton - activates an RNA to degrade viral RNA
- Mx protein blocks viral transcription
What are the actions of dendritic cells and macrophages?
- phagocytosis
- antigen presentation
- release of cytokines
- killing of virus infected cells
What are the actions of NK cells?
- cytotoxic to virus infected cells
- release INF gamma to activate T cells
How does the adaptive immune system attack viral infections?
- T cells resolve infection
- ABs contribute to recovery and memory
Why is immunologic memory needed?
- ensures protection in times when immuncomprimised
What are some anti-host actions of a virus?
- antigenic variation, shift or drift
- molecular mimicry
- latency or reducing expression on cells
- impair host response
What is a pathologic consequence of immune response to a viral infeciton?
- excessive cytokine production can lead to Acute Respiratory Distress Syndrome
- antibodies can form immune complexes leading to glomerulonephritis
- T cells cause host tissue damage (autoimmunity)
What are the four major categories of Fungi?
- Superficial mycoses - jock rot, athletes foot
- Subcutaneous mycoses - malssezia furfur
- Respiratory mycoses - aspergillosis, histoplsmosis, blstomycosis
- Candida albicans (yeast infection)
What is the major form of immunity against fungi?
- innate reponse by neutrophils and macrophages
What is the bodies immunity against parasitic infections?
- innate immunity (complement, macrophages, neutrophils, eosinophils, mast cells)
- IgE AB activate eosinophils and mast cells
How does parasitic infections escape the immune system?
- resist destruction by complement system
- resistant to oxygen metabolites and lysozymes
- antigen variation
What is the general concept of immunization?
- generating specific immunological memory by use of a less virulent microbe/toxin
- induce long lived pool of specific memory
What is meant by herd immunity?
- vaccinated individuals will prevent the spread of infection
What are examples of passive immunization?
- IgG and IgA in infants and fetus
- specific Gamma Globulin
- Monoclonal antibodies
What makes an effective vaccine?
- safe
- protective
- gives sustained protection
- induces neutralizing antibody
- induces protective T cells
- Practical
- Need a good antigen (live, dead intact, fragments, toxoid)
What are some examples of live (Attenuated) viral vaccines?
- small pox
- polio
- measles
- mumps
- rubella
- yellow fever
- Varicella-zoster
- Rotovirus
- Influenza
What are some examples of inactivated vaccines?
- Polio (Salk)
- Rabies
- Influenza
- Hep A
What are some examples of fragmented or subunit vaccines?
- Hep B (surface antigen)
- Human papilloma virus (recombinant capsid)
What are some examples of bacterial vaccines?
- BCG - tuberculosis (live)
- Typhoid (live)
- Pertusis (inactivated)
- Cholera (inactivated)
- Anthrax (Inactivated)
What are some examples of bacterial subunit vaccines?
- typhoid - polysaccharide
- Hib
- Meningococcus
- Pneumococcal - capsular varients
- Lyme disease
What are some examples of toxoid vaccines?
- diphtheria
- tetanus
Why are there no vaccines at present for parasitic infections?
- genome is similar to ours
- immune response is poor
- parasites will evade immunity
What are some new approaches for vaccine development?
- new adjuvants and delivery systems
- DNA vaccines
- using other viral vectors to integrate surface glycoprotein production
What are the adverse effects associated with vaccines?
- pain, fatigue, headache, egg allergy
- live vaccines cannot be given to immunocompromised
