Biology 1001A : bio final exam notes all lectures
10 Mar 2015
School
Department
Course
Professor
Lecture 2: HIV 03/10/2015
Lecture 2: HIV
Independent Study Outcomes:
General mechanisms by which vaccines protect against diseases
Create catch of weapons for immune system, deployed when needed
Pre-immunization allows faster attack on disease/virus
HIV Vaccines:
Vaccine trains body to recognize/neutralize invader
Penetrates mucosal barriers; affects immune cells to replicate
Macrophages capture and display pieces of HIV
Memory cells from vaccine activated, when learned from front line troops
Memory B cells turn into plasma cells; generate specific antibodies to latch
onto HIV to prevent cell infection
Killer T cells seek out and kill already infected cells
why developing a vaccine against HIV is relatively challenging,
compared to other diseases
Furiously mutating pathogen
Quickly hides itself, much more genetic variation than flu
Today evidence that HIV vaccine possible
Broadly-neutralizing antibodies discovered, new site found on virus they
can latch onto
why people are encouraged to get a flu vaccine each year (as
opposed to one time only).
Mutated flu virus (H&N spots) prevents previously-existing antibodies to
attach and neutralize virus
Birds carry all types of influenza- (swine from birds in mexico)
Lecture Outcomes:
What is HIV?
HIV is a retrovirus containing two copies of single stranded RNA (every
living thing stores in DNA)
Contain reverse transcriptase, targets immune system
Reverse transcriptase synthesizes complementary DNA from mRNA,
allowing cloning of actively expressed genes
Has 9 genes, one controls reverse transcription
Rapidly mutates because Reverse transcriptase doesn’t have proofreading
enzymes like normal DNA polymerase, errors persist in synthesis of DNA
from RNA
general global distribution of HIV infections
AIDS associate with HIV is a pandemic affecting all inhabited continents
Most prominent Sub-Saharan Africa (40% in Botswana)
33.4 million affected with HIV in 2012
90% of kids under age 15 in S.A. have HIV
general temporal trends in HIV infection rates
# of people living with HIV: continues to increase
#of children living with HIV: continues to increase
# of orphans due to AIDs: continues to increase
#of death due to AIDS (adults and children): plateaus
factors that explain why no cure or universal vaccine has been
developed for HIV/AIDS
2
very fast mutation rate
problematic to find drugs that don’t simulatenously kill the host
Lack of economic motivation, companies get more money for treatment
Relatively new virus (only found within humans in last 30 years)
reasons why viruses are not considered “alive”
Don’t belong on tree of life, can’t self reproduce
Are not cellular, which is requirement for life must infiltrate host to function
Obligate cellular parasites: parasites reproduction entirely reliant on
intracellular resources. (bacteria can be this)
reasons why anti-viral drug therapies often have serious side effects.
In order to effectively work, they must take out host cells in the process
Evolution of viruses:
1st thought:
Viruses evolved after cells appeared as “escaped” fragments of DNA,
surrounded by protein and escaped parent cells
2nd thought:
origination from “primordial gene pool”
viruses have NO common ancestor
play important role in evolution of cellular life
major steps in life cycle of HIV
3
