The early immune response to HIV-1 infection is likely to be an important factor in determining the clinical course of disease. Recent data indicate that the HIV-1 quasispecies that arise following a mucosal infection are usually derived from a single transmitted virus. Moreover, the finding that the first effective immune responses drive the selection of virus escape mutations provides insight into the earliest immune responses against the transmitted virus and their contributions to the control of acute viraemia. Strong innate and adaptive immune responses occur subsequently but they are too late to eliminate the infection. In this Review, we discuss recent studies on the kinetics and quality of early immune responses to HIV-1 and their implications for developing a successful preventive HIV-1 vaccine.
Answer:
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Explanation:
Answer:
It allows rapid conduction of water from one vessel element to the next.
Explanation:
Vessels are one of the two types of conducting cells of xylem. Vessels are made of vessel elements. Vessel elements are the individual cells with perforation plates. The perforation plates have large holes (perforations). Perforation plates of adjacent vessel elements allow easier conduction of water from one vessel element to the next.
The perforated end walls of vessel elements allow these conducting cells to conduct water more readily than tracheids. Stacking of vessel elements with perforated end walls make the vessel like a water pipe through which water is being readily conducted.
Answer:
B
Explanation:
This is the only thing missing in the food chain
Because cells need insulin for glucose from the blood if they don’t have enough glucose it can build up in the blood and that causes the tiredness. Glucose is needed to create energy otherwise you would end up tired.
