Using what you’ve learned from your reading, please respond thoughtfully and in your own words to the following discussion questions. Number each question and be sure to back up statements of fact...

1. Injections of TC cells completely removed all Hepatitis B viruses from infected mice, but
the injections killed only 5% of the infected liver cells. Explain how TC cells cured the mice.
This is usually assumed that viral clearance is chiefly governed by the antigen-specific T
cells that could also lead towards destruction of infected cells, but it is not true in the case of all
viruses. A current research study based on a transgenic mouse infected by Hepatitis B virus has
revealed that adoptively transmitted, virus-specific cytotoxic T lymphocytes (Tc cells) are able
to remove Hepatitis B virus through interrupting with expression of its genes and during this
task, they do not exhibit any adverse impact on hepatocytes (liver cells). It can be possible due to
the cytokines generated by Tc cells after detection of antigen(s). This is renowned as
noncytopathic cytokine-dependent 'curative' procedure which can boost the shielding effect(s) of
immune system in a significant manner. That’s why; researchers are trying to find out the
importance of curative methods of viral elimination in other models of viral diseases too (Chisari
& Ferrari, 1995).
2. A patient with AIDS has a low TH cell count.
(i) Why does this patient have trouble making antibodies?
Though, cellular and humoral immunity appear diverse by nature, but according to
experts, a close linkage can be identified between them. In fact, after recognition of surface
markers present on cells/ antigens, T-helper cells send signal to killer CD-8
+
cells so that, these
could struggle against such harmful agents. Besides, cytokines can also be liberated by T-cells
that may induce B-cells for antibody production. For that reason, if TH cell count is reduced then
generation of antibodies may also get affected in an adverse mode for instance, in AIDS patients
HIV may spoil T-cell repertoire which can lead towards the development of opportunistic
illnesses due to suppression of cellular and humoral immune response (Baehrecke, 2002).
(ii) How does this patient make any antibodies?
Above problem might be overcome with the help of IL-2 that can assist T-helper cells in
production of sufficient replicas so that, these could defeat the harm done by HIV and stimulate
the production of antibodies too (Costello et al., 2009).
3. Newborns (under 1 year) that contract dengue fever have a higher chance of
dying from it if their mothers had dengue fever prior to pregnancy. Explain why.
Dengue may predispose to definite pregnancy complications which can prove to be
terminal for an infant. For example, due to transplacental infection harsh fetal or neonatal
illnesses can take place. Besides, because of presence of maternal antibodies in infants risk of
Severe dengue /Dengue Hemorrhagic Fever (DHF) can be increased in them. Dengue
Hemorrhagic Fever (DHF) can be defined as an acute, life-threatening, capillary leak syndrome
which might occur because of dengue virus infection (Costello et al., 2009).
Though, its pathogenesis could not be understood clearly, yet according to the researches,
infants (less than 1 year) infected with dengue virus can be called at high risk for DHF if they
contain maternal antibodies to dengue virus at sub- neutralizing levels means; DHF can occur
due to antibody enhancement of viral infection. Virus enhancement happens due to presence of
sub- neutralizing levels of maternal placentally transferred antibodies to dengue virus which can
cross-link virus and Fc receptor-bearing cells like macrophages. Such cross-linking can induce
the uptake of virus and may lead...