HIV 1

Bushra Rehman

FA08-BBS-004

RETROVIRUS

HIV 2

TABLE OF CONTENTS• INTRODUCTION OF RETROVIRUS

• GENOME AND STRUCTURE OF RETROVIRUS

• HISTORY OF HIV

• TYPES OF HIV

• TRANSMISSION OF HIV

• GENOME AND STRUCTURE OF HIV

• REPLICATION OF HIV

• IMMUNE RESPONSE TO HIV

• THERAPY

• SIGNS AND SYMPTOMS OF HIV

• COMMON MYTHS ABOUT HIV

HIV 3

RETROVIRIDAE• In 1908, retroviruses were found by Vilhelm Ellermann and Oluf Bang

• Unlike other viruses

• RNA → DNA → RNA → protein via reverse transcriptase

• And then integrated in to the host genome Provirus

• Human Immunodeficiency Virus (HIV) is one of the members of this family

• Another member is feline leukemia

HIV 4

GENOME AND STRUCTURE• Retroviridae has a positive sense, single-stranded RNA and is linear

• 3’ polyadenylated tail and 5’ cap

• have reverse transcriptase

HIV 5

• An envelope, a nucleocapsid and a nucleoid

• have spherical enveloped virions to pleomorphic enveloped virions which are measured 80nm to 100nm in diameter

• Within the icosahedral capsid, it has a central nucleoid that consists of ribonucleoprotein

• The capsid is enveloped with glycoprotein

STRUCTURE

HIV 6

• Acquired Immunodeficiency Syndrome (AIDS) is caused by HIV

• AIDS is being spread worldwide

• AIDS can be transmitted via sexual contact and any form of contacts with blood. Mother passes the AIDS disease to the child via placenta, mucosa and breast milk

HIV

HIV 7

“It all started as a rumour… Then we found we were dealing with a disease. Then we realised that it was an epidemic. And, now we have accepted it as a tragedy.” - Chief epidemiologist in Kampala, Uganda

HIV 8

• evidence that HIV originated in Africa

• A 10-year study completed in 2005 found a strain of Simian Immunodeficiency Virus (SIV) in a number of chimpanzee colonies in south-east Cameroon that was a viral ancestor of the HIV-1 that causes AIDS in humans

HISTORY

HIV 9

ADULT HIV PREVALENCE (%) IN AFRICA BETWEEN 1988 AND 2003

HIV 10

HIV TYPES, SUBTYPES GROUPS AND STRAINS

• HIV is a highly variable virus which mutates very readily

• many different strains of HIV, even within the body of a single infected person.

• two types of HIV: HIV-1 and HIV-2

• . Both types are transmitted by sexual contact, through blood, and from mother to child, and they appear to cause clinically indistinguishable AIDS.

• that HIV-2 is less easily transmitted

HIV 11

• strains of HIV-1 can be classified into four groups

• "major" group M, the "outlier" group O and two new groups, N and P

• Group O restricted to west-central Africa

• group N - a strain discovered in 1998 in Cameroon - is extremely rare

• group M at least nine genetically distinct subtypes; A, B, C, D, F, G, H, J and K

HIV – 1 SUBTYPES

HIV 12

DOES SUBTYPE AFFECT DISEASE PROGRESSION?

• in 2006 found that Ugandans infected with subtype D or recombinant strains incorporating subtype D developed AIDS sooner than those infected with subtype A, and also died sooner

• subtype D is more virulent because it is more effective at binding to immune cells

• women infected with subtype C, D or G were more likely to develop AIDS within five years of infection than those infected with subtype A.

HIV 13

TRANSMISSION• HIV is transmitted through direct exchange of body fluids

• Sexual intercourse is the most common mode of transmission

• Blood to blood contact, such as through sharing needles for intravenous injection or blood transfusion can also transmit HIV

• Infected mothers can pass HIV to their infants during pregnancy, birth and breastfeeding

HIV 14

HIV 15

• Outside of a human cell, HIV exists as roughly spherical particles (sometimes called virions). The surface of each particle is studded with lots of little spikes.

• surround themselves with a coat of fatty material known as the viral envelope

• 72 little spikes formed from the proteins gp120 and gp41

• below the viral envelope is a layer called the matrix, which is made from the protein p17.

• viral capsid made from protein p24, core are three enzymes required for HIV replication called reverse transcriptase, integrase and protease, is HIV's genetic material, which consists of two identical strands of RNA

THE STRUCTURE OF HIV

HIV 16

HIV REPLICATION CYCLE

• Entry

• Reverse Transcription and Integration

• Transcription and Translation

• Assembly, Budding and Maturation

HIV 17

HIV 18

HIV 19

IMMUNE RESPONSE• Macrophages and dendritic cells on the surface of mucous membranes bind virus and

shuttle it into the lymph nodes, which contain high concentrations of helper T cells

• the immune system initiates anti-HIV antibody and cytotoxic T cell production

• it can take one to six months for an individual exposed to HIV to produce measurable quantities of antibody

• The immune response is weakened as memory T cells (CD4+ CCR5+) are destroyed.

HIV 20

THERAPY

• There are four types of AIDS therapy.• 1. Non-specific therapeutic management• 2. Specific therapeutic management• 3. Immunomodulation• 4. Vaccines

HIV 21

HIV 22

WHY IS IT DIFFICULT TO DEVELOP A VACCINE FOR HIV

• Developing a vaccine is a very difficult challenge for scientists. There are many reasons for this, including:

• Nobody has ever recovered from HIV infection, so there is no natural mechanism to imitate

• HIV destroys the immune system cells that are meant to fight against it

• Soon after infection, HIV inserts its genetic material into human cells, where it remains hidden from the immune system

• HIV occurs in several subtypes, each of which is very different from the others

• Even within each subtype, HIV is highly variable and constantly changing

• There are no good animal models to use in experiments although the use of non human primate (NHP) models could become a more significant model for HIV vaccine design and testing in the future.

HIV 23

• Early Signs and Symptoms of HIV

• Headache

• Tiredness

• Nausea

• Diarrhea

• Fever

• Enlarged lymph nodes in the neck, armpits or groin

• Later Signs and Symptoms of HIV/AIDS

• rapid weight loss.

• dry cough.

• recurring fever or profuse night sweats.

• profound and unexplained fatigue.

• swollen lymph glands in the armpits, groin, or neck.

• diarrhea lasting more than a week.

• white spots or unusual blemishes on the tongue, in the mouth, or in the throat.

• pneumonia.

• red, brown, pink, or purplish blotches on or under the skin or inside the mouth, nose, or eyelids .

• memory loss, depression, and other neurological disorders

SIGNS AND SYMPTOMS

HIV 24

HIV 25

COMMON MYTHS

• You cant have a baby if you or your partner is HIV positive

• If you get HIV you’ll die soon

• It takes months before you can have a test and get the result to find out if you have HIV

• You can get HIV from someone who bites or spits at you

• Its very easy for me to catch HIV form someone who is infected

• You can get HIV by having a fish pedicure.

HIV 26

REFERENCES• http://virology-microbiology-b.blogspot.com/2009/01/retroviridae-and-flaviviridae.html

• http://www.hivaware.org.uk/

• http://www.hivaware.org.uk/be-aware/common-myths.php

• http://library.thinkquest.org/10631/allabout/history.htm

• http://www.bupa.co.uk/individuals/health-information/directory/h/aids

• http://www.bbc.co.uk/health/physical_health/sexual_health/stis_hivaids.shtml

• http://www.lfpress.com/news/london/2011/12/21/19154836.html

• http://www.nhs.uk/conditions/HIV/Pages/Introduction.aspx

• http://www.mcld.co.uk/hiv/?q=HIV%20genome

• http://www.biology.arizona.edu/immunology/tutorials/AIDS/HIVimmune.html

• http://menshealth.about.com/od/conditions/a/HIV_signs.htm