Other Infectious Agents and Vaccines

• naked protein--variants of PrP^c (involved in a number
• Interact with endogenous cellular proteins
• form neural plaques and tangles
• causes diseases called spongiform encephalopathies
• Two types: TSE (transmissible) and GSE (genetic/rare)

the variants have a primary sequence identical to the primary sequence of normal proteins; what differs is the secondary and tertiary structure

prions can dimerize/ acid resistant/ resistant to proteinases/ can't break them down

it naturally maintains myelin on myrlinated axons, prevents lysis from osmosis, etc.

• Observed in New Guinea during the 1920s
• Ritualistic cannibalism: consumed the tissues, including brain of deceased family and battle enemies; brain tissue from individuals with kuru was highly infectious; prion was transmitted via eating or sores/ cuts

Parkinsonian movement (6 ms-1 yr) and dementia (1-2 years)

PrP^k

three types: classic, variant, familial

• Parkinsonian symptoms
• new: 1999-2000

• onset over age 60
• sporadic (sCJD)

• onset below 30
• acquired (vCJD or iCJD); 
• 2 years

familial; occurs in families where genetic mutations allow them to form

• first infections of BSE occurred in the 1970s; two being identified in 1986
• result of feeding cattle meat-and-bone meal that contained Scrapie/ BSE-infected material
• Strong epidemiologic evidence for a causal association with vCJD
• first reported from UK in 1996

naked nucleic acids that can be as small as 22 nucleotides

infects damaged plants, causing color changes, wilting leaves, root rot, plant death, stunted growth; affects chloroplast; uses it as a base to begin replication

-plant reservoirs

- related to introns 

two families (PSTVD/ ASBVd)

• attachment blcokers
• penetration and uncoating blockers
• genome relication inhibitors
• gene expression
• inhibitors of assembly, aturation, and release

• viral attachment mimetic
• - Anti-receptor antibodies
• - Anti-idiotype antibody to viral particle
• - Natural receptor ligands & agonists
• - Peptides that mimic the receptor binding domains

they are unspecific and have several issues

• mimic the receptor and bind the virus
• anti-virus antibodies
• receptor anti-idiotyp antibodies
• extraneous receptor
• synthetic receptor mimetic (sialic acid for influenza)

• •The drugs generally interfere with proteins
• –Two common drugs interfere with endosomal enzymes that inhibit HA conformational changes
• •Amantadine                             Rimantadine

The capsids can't break down and uncoat/ viral components can't get out

• •These drugs are polymerase and protease inhibitors
• •Many of these drugs are nucleoside analogs
• –Pro-drugs
• –Phosphorylated for activity
• •Toxicity varies between analogs

• •Engineered proteins
• –Interfere with enzymes
• •Oligonucleotides
• –Bind RNA
• •Non-nucleotide RT inhibitors
• –Bind enzymes directly

• •Interfere with late stage processes
• •Tamiflu and Relenza

whole agent and subunit

• - live
• - inactivated by formalin (rabies, salk polio)
• - attenuated: replicate a very mild case; agent replication increases the dose; mutation issues; reuces the virulence of the pathogen

erecombinant: protein or portion expressed in a vector (Hep B)

toxoid: inactivated toxin (tetanus/ diptheria)

conjugated: immunogenic molecule fused to a protein (strep pneumonia)

acellular: fraction organisms (pertussis)