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10/10/2008

Ten ‘schooled’ Kenyans hold Key to an HIV Vaccine

Filed under: disease/health,kenya — admin @ 12:20 pm

Local scientists have managed to identify 10 HIV positive Kenyans with an antibody that could hold the key to developing an effective AIDS vaccine.

The individuals, who the scientists say have powerful antibodies that neutralise the virus, stopping it from infecting new cells, have neither used any antiretroviral drugs nor been attacked by opportunistic infections despite living with the virus for over nine years.

On being screened, the individuals were found to possess high CD4 count–immune cells used to fight infections–and very low viral loads-amount of HIV in the body-, which were uncharacteristic of an infected person.

They also have very low possibilities of transmitting the virus to another individual as well as being able to delay progression to AIDS, the last stage of the disease where opportunistic infections reign, killing the individual if not well managed.

This means if a vaccine that elicits these antibodies is developed; it would significantly cut down on the number of new infections in Kenya and other HIV hotbeds.

The 10 individuals are now being followed to establish who among them qualify to be what scientists refer to as Elite Controllers-individuals who are able to control HIV viral load to less than 50 copies compared to over 30,000 copies of HIV in a person without such antibodies.

“This new phenomenon is being seen in both men and women who we have screened in Nairobi, and we are keenly following them to identify the key antibodies that make them tick,” says Prof Omu Anzala, the Director of Kenya Aids Vaccine Initiative.

Disclosing the findings, Prof Anzala said those screened so far have an immune system able to elicit antibodies – CD4 and CD8- with a unique protein that target specific sites of HIV stopping it from infecting new cells.

In Africa, of the 1,700 HIV positive people who been screened in the past one year, 170 have HIV neutralising antibodies. Kenya, Uganda, Rwanda, South Africa, and Zambia, are some of those marked to help in solving this problem.

In Africa, of the 1,700 HIV positive people who been screened in the past one year, 170 have HIV neutralising antibodies. Kenya, Uganda, Rwanda, South Africa, and Zambia, are some of those marked to help in solving this problem.

“What we are experiencing now is phenomenal and provides critical information of how we move forward and the massive work we need to undertake in this direction,” says Dr Wayne Koff, of International Aids Vaccine Initiative (IAVI).

In interview, Wayne said they have managed to identify four antibodies with ability to neutralise the virus and are currently studying them to see which ones are broadly neutralising-those with ability to neutralise different types of HIV strains such as A, B, C and D.

In this quest, they are also paying particular attention to immune systems of individuals who have lived with HIV for the past three years without using ARVs. Some of them are believed to possess the neutralising antibodies.

Buoyed by these new findings, IAVI is going to set aside between 30 and 50 per cent of its budget on vaccine discovery on the identification and development of a vaccine with the ability to elicit broadly neutralising antibodies, according to Dr Koff.

Likewise, IAVI has developed what they call Protocol G, whose sole objective is to help scientists identify elite controllers across Africa and other parts of the world.

Identifying the broadly neutralising antibodies and then using the knowledge to develop a vaccine to produce similar responses in HIV negative individuals has been the most difficult thing for scientists. It has taken them over 10 years to just understand this phenomenon well.

Speaking recently in Nairobi to a group of scientists from Africa, Dr Koff admitted that “as a field we have not understood as yet how to elicit broadly neutralising antibodies to tackle HIV.”

“But now,” adds an elated and optimistic Prof Anzala, “we are on the path to somewhere and can see light at the end of the tunnel.”

The closet the scientists came to generating neutralising antibodies was during the Vaxgen vaccine trials. It never worked as the vaccine failed to elicit such antibodies in amounts necessary to control HIV infection.

Still, there other challenges even with the new discovery. The four neutralising antibodies identified so far work on just one site of HIV, when they are need to do so on various points to be able to disable it effectively. Consequently, the search is now on to find other antibodies that work on different sites of the virus.

Discovery of these antibodies will help the scientists develop a vaccine with the ability to disable a wide range of HIV strains such as A, C, and D, which are circulating in Kenya.

As for now, the four antibodies discovered are crucial since unlike the cellular immune response that destroys a cell once infected and on which past vaccines have been developed; the neutralising antibodies are able to prevent the virus from infecting the cell in the first place.

Studies in the primates have already shown that broadly neutralising anti-bodies to possess the ability to prevent infection.

This encouraging information has led scientists to establish Neutralising Antibody Consortium, whose sole responsibility is pick-up more antibodies with ability to prevent HIV infection. Formed in 2002, the Consortium has grown from four academic institutions to 18 now.

But as they undertake all these initiatives, scientists believe a vaccine that produces both broadly neutralising antibodies and cellular immune response would be the most effective one in controlling the virus.

Cellular immune response is where the immune system cells identify and kill the infected CD4 cells. These two approaches are going to require massive investment as well as facing numerious challenges.

In its AIDS Vaccine BluePrint 2008: A Challenge to the Field, A Road Map for Progress, IAVI is acutely aware of this fact.

IAVI admits that the virus remains difficult to contain because of its HIV immune evasion mechanisms, is sexually transmitted, and has high capacity of recombination, among others.

•••

‘Sexually-transmitted grades’ kills quality education

Plan International warns children of all ages, both genders, are vulnerable to school violence

Sexual exploitation in African schools has become so widespread that children have come up with their own terms to refer to sexual relations with their teachers.

From ‘Sexually Transmitted Grades’ to ‘BF’, or bordel fatigue, which refers to exhaustion from multiple sexual activities with teachers, this slang hints at the prevalence of exploitation in Africa’s learning environments.

The lexis of abuse was discovered during research for Plan International’s (PI) latest report, ‘Learn Without Fear,’ part of the organisation’s global campaign to end violence in schools.

“We’ve been aware of the problem for a long time but we’ve had to just go on anecdotal evidence of violence and its effects,” John Chaloner, PI Regional Director for West and Central Africa, told IRIN. “What this report has done is to talk to children, to teachers and to parents. So now we’re dealing with evidence not hearsay”.

Drop out danger

As schools reopen throughout Africa, the report reveals alarmingly high levels of violence, which are undermining government efforts to provide quality education. The report concluded many girls and boys are dropping out of school as a result of sexual abuse and corporal punishment.

“Our teachers should be there to teach us and not to touch us where we don’t want,” a 15 year-old girl from Uganda told PI, “I feel like disappearing from the world if a person who is supposed to protect me, instead destroys me”.

According to the report, research in Uganda found that eight per cent of 16 and 17 year-olds had had sex with their teachers. In South Africa, at least one-third of all child rapes are by school staff. In a survey of ten villages in Benin, 34 per cent of children confirmed sexual violence in their schools.

While boys usually suffer more violent – and possibly deadly – corporal punishment at the hands of their teachers than their female classmates, sexual harassment and exploitation appear to be overwhelmingly carried out against girls. The report found girls are vulnerable to attacks not only from teachers and other care givers, but also from male students, either at school or on the journey to or from school.

“Teachers often justified the sexual exploitation of female students by saying that their clothes and behaviour were provocative, and that they, the teachers, were far from home and in sexual need,” according to PI’s report.

Sex exchange

What can appear a ‘grey area’ in this situation is the apparent collusion of some female students.

‘Africell’, or ‘a free sell’ has been coined to describe girls who do not wear underwear to provoke teachers into sexual activities in exchange for good grades or ‘sexually transmittable means’ – food, school materials or school fees.

But these girls are not the instigators, said Atoumane Diaw, Secretary General of the National Union of Elementary Teaching in Senegal.

“These children are often encouraged by their parents. Do you think a ten year-old is going to buy herself ‘sexy’ clothes? No, it is the system, it is society that is corrupt. These poor families need [financial] help so they won’t put themselves into this situation”.

In addition to financial assistance, Diaw suggested practical measures for schools: “A modest uniform for students so everyone looks the same. Separate toilets for boys, girls or teachers. And surveillance so that the teacher is not left alone with a pupil after class”.

Poverty facilitates the abuse, according to PI. Children are increasingly responsible for the economic welfare of their families; teachers are often underpaid, or not paid at all, with some seeing sexual favours from students as ‘compensation’.

Authors of the report noted that in many African cultures, corporal punishment is often viewed as an acceptable form of discipline. Social norms that encourage male aggression and female passivity are also seen to champion various forms of violence against girls.

Speak out

“We need to educate people so we tackle the problem [of violence] before it happens.” said Atoumane Diaw. “Our campaign is…raising awareness with teachers. We’re educating children about their rights and their worth. Laws have to be harmonised and enforced in different countries. We must go forward together, fight together.”

The Kenyan education ministry recently launched guidelines on school safety after a recent deadly spate of high school student riots.

Violence in schools, and particularly sexual violence, is chronically under-reported because of cultural norms, students’ feeling of shame, and because they do not know in whom they can confide, according to PI’s report. It adds teachers are often reluctant to report colleagues’ abuse.

“As adults, we need to be watchful, we need to be alert.” PI’s John Chaloner told IRIN, “Children need outlets, like help lines, so they can express themselves. We need to get the message out so that children will no longer be harmed by the very people who should be protecting them”.

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