Health and Medicine Women often report that they feel colder than men in the same environment. Why is there such variation in our reaction to cold? The perception of cold begins when nerves in the skin send impulses to the brain about skin temperature.
Abstract The biological correlates of an effective immune response that could contain or prevent HIV infection remain elusive despite substantial scientific accomplishments in understanding the interactions among the virus, the individual and the community. The observation that some individuals appear to possess resistance to HIV infection or its consequences has generated a host of epidemiologic investigations to identify biological or behavioral characteristics of these individuals.
These data might hold the keys to developing appropriate strategies for mimicking the effective responses of those who appear immune. In this paper we review genetic mechanisms including the role of chemokines and their receptors, cytokines, host genetic immune response to HIV infection, local immune response correlating with behavioral variables, co-infection and immune based mechanisms that have been elucidated so far.
We offer suggestions for how to use these observations as platforms for future research to further understand natural resistance to HIV infection through cohort studies, population genotype sampling, mathematical modeling of virus—host interactions and behavioral analyses.
Resistance, HIV infection, Susceptibility, Progression Introduction Since the reporting of the first cases of AIDS inand the discovery of its etiologic agent, human immunodeficiency virus type 1 HIV-1inthere has been substantial scientific progress in the development of both effective antiretroviral therapy and the understanding of virus—host cellular interactions.
Nonetheless, the correlates of effective immunity to HIV remain elusive, and the paucity of knowledge has hindered development of effective vaccines. One approach to understanding the immune response to HIV and why it fails in most people lies in examining those few hosts who appear to be resistant either to acquisition of the virus or to its devastation once acquired.
Two phenomena have indicated that natural resistance to HIV-1 infection, while rare, does exist.
First, there are individuals who have been exposed to HIV, in some cases repeatedly and over long periods of time, who have remained HIV-uninfected. Long-term non-progressors have been identified among various groups, including homosexual men, women, injection drug users and children.
Current HIV vaccine studies would be viewed as successful if they achieved either prevention of initial infection or amelioration of disease. As natural mechanisms appear capable of accomplishing both goals, it benefits us to study individuals in whom these mechanisms seem to be operating.
Here we will review the evidence for HIV-1 resistance and discuss a research agenda for the field. Factors Affecting Susceptibility and Disease Progression Chemokine and Chemokine Receptor Polymorphisms Chemokines are chemoattractant cytokines, which are small peptides that are secreted by cells and serve to regulate chemotaxis the movement of cellsadhesion, and the activity but not the proliferation of immune responsive cells and tissues.
Once secreted, chemokines attach to other cells via chemokine receptors present on the target cell surface. Eighteen chemokine receptors have been identified, each of which can accept more than one chemokine and often accept many.
Others may instead carry one or two copies of a mutated form of the gene coding for the receptor. In some cases, mutations or polymorphisms affect the binding characteristics of the receptor. HIV-1 needs two receptors to gain entry into human cells: Once HIV has bound to CD4 and a chemokine receptor, an area of the virus is exposed that can fuse with the human cell and permit entry of viral genetic material into the cell.
A schematic of this entry process is shown in Fig.Some resistant people have been found who have two perfectly normal copies of CCR5.
So other genes also contribute to slowing down HIV infection, and scientists are busy trying to identify them. The usefulness of this work is mainly in how it helps us understand how the virus works and points to new possibilities for drugs to treat infection.
Aug 30, · After exposure to the flu virus, some of us are bed-ridden for days, while others never seem to get sick. New research hints at an explanation to why some people never seem to .
But some healthy people can feel colder than do others in the same environment. Women often report that they feel colder than men in the same environment.
Researchers are trying to find out why some people carry a genetic mutation that makes them highly resistant to HIV infection. This mutation, called Delta32, keeps a protein called CCR5 from rising to the surface of the immune system’s T cells.
These feelings motivate us to perform certain behaviours, such as curling up or putting on more clothes, and to complain.
But some healthy people can feel colder than do others in the same. For as long as disease has existed, there have been a select few people who have a natural resistance to certain illnesses. Whether it be a virus or genetic condition, natural resistance has long been documented and, for the most part, continues to baffle scientists.