immunity pictures

موضوع: رد: immunity pictures الأحد 13 يناير 2008, 6:24 pm

انتظروا مزيد من الصور
with more specifoc

موضوع: رد: immunity pictures الأحد 13 يناير 2008, 7:15 pm

mercieeeeeeeeeeeeeeeee

موضوع: رد: immunity pictures الأحد 13 يناير 2008, 7:20 pm

Useful Pics, waiting more and thank you very much

موضوع: رد: immunity pictures الأحد 13 يناير 2008, 7:21 pm

شكرا ياايمى على الصور جزاك الله كل الخير

موضوع: رد: immunity pictures الإثنين 14 يناير 2008, 12:36 am

اقتباس :: thx alot
plz try to fix this proplem[&hide u name f u want]thanks again

والله انا مش عارفه هي بتعمل كدا ليه
انا بحطها عادي زي اي صوره
بس هشوف كدا ان شاء الله

موضوع: رد: immunity pictures الإثنين 14 يناير 2008, 12:38 am

thx & waiting for more

موضوع: رد: immunity pictures الإثنين 14 يناير 2008, 1:22 am

Good efforts & waitinG 4 More

:face:

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 5:00 pm

[

representation of T-cell receptors and viral–MHC
antigen complexe

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 5:02 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 5:02 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:36 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:36 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:37 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:38 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:40 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:42 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:49 pm

من الاخر ده موضوع يستحق التثبيت

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 6:51 pm

هههههههههههههههههههههههههههه

براحه علينا مش لاحق أسيف الصور

كل أما ادخل ألاقى صور جديده اترفعت

*********

"" شكــــــــــــــــــــرا جدااااااا على الصور ""

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 7:21 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 7:23 pm

1. The Immune System
The immune
system is a bodywide network of cells and organs that has evolved to
defend the body against attacks by "foreign" invaders.
The proper targets of the immune defenses are infectious organisms—bacteria such as these streptococci;

Fungi (this one happens to be the mold from which penicillin is made);
Parasites, including these worm-like microbes that cause schistosomiasis; and
Viruses such as this herpes virus.

2. Markers of Self
At the heart of the immune response is the ability to distinguish between self and nonself.
Every body cell carries distinctive molecules that distinguish
it as "self." Normally the body's defenses do not attack tissues that
carry a self marker; rather, immune cells coexist peaceably with other
body cells in a state known as self-tolerance.

3. Markers of Non-Self
Foreign molecules, too, carry distinctive markers, characteristic shapes called epitopes that protrude from their surfaces.
One
of the remarkable things about the immune system is its ability to
recognize many millions of distinctive non-self molecules, and to
respond by producing molecules such as these antibodies—and also
cells—that can match and counteract each one of the non-self molecules.
Any substance capable of triggering an immune response is
known as an antigen. An antigen can be a bacterium or a virus, or even
a portion or product of one of these organisms. Tissues or cells from
another individual also act as antigens; that's why transplanted
tissues are rejected as foreign.

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 7:25 pm

7. Cells of the Immune System
Cells destined to become immune cells, like all blood cells, arise in the bone marrow from so-called stem cells.
Some
develop into myeloid cells, a group typified by the large, cell- and
particle- devouring white blood cells known as phagocytes; phagocytes
include monocytes, macrophages, and neutrophils. Other myeloid
descendants become granule-containing inflammatory cells such as
eosinophils and basophils. Lymphoid precursors develop into the small
white blood cells called lymphocytes. The two major classes of
lymphocytes are B cells and T cells

8. B Cells
B cells work chiefly by secreting soluble substances known as antibodies.
Each
B cell is programmed to make one specific antibody. When a B cell
encounters its triggering antigen (along with various accessory cells),
it gives rise to many large plasma cells. Each plasma cell is
essentially a factory for producing that one specific antibody.

9. Antibody
Each antibody is made up of two identical heavy chains and two identical light chains, shaped to form a Y.
The
sections that make up the tips of the Y's arms vary greatly from one
antibody to another; this is called the variable region. It is these
unique contours in the antigen-binding site that allow the antibody to
recognize a matching antigen, much as a lock matches a key. The stem of the Y links the antibody to other participants
in the immune defenses. This area is identical in all antibodies of the
same class—for instance, all IgEs—and it's called the constant region.

10. IgG, IgD, and IgE
Antibodies belong to a family of large protein molecules known as immunoglobulins.
Scientists
have identified nine chemically distinct classes of human
immunoglobulins, four kinds of IgG and two kinds of IgA, plus IgM, IgE,
and IgD. Immunoglobulins G, D, and E are similar in appearance. IgG,
the major immunoglobulin in the blood, is also able to enter tissue
spaces; it works efficiently to coat microorganisms, speeding their
uptake by other cells in the immune system. IgD is almost exclusively
found inserted into the membrane of B cells, where it somehow regulates
the cell's activation. IgE is normally present in only trace amounts,
but it is responsible for the symptoms of allergy.

11. IgA and IgM
IgA a doublet
concentrates in body fluids such as tears, saliva, and the secretions
of the respiratory and gastrointestinal tracts. It is, thus, in a position to guard the entrances to the body.
IgM
usually combines in star-shaped clusters. It tends to remain in the
bloodstream, where it is very effective in killing bacteria.

12. Antibody Genes
Scientists long
wondered how all the genetic information needed to make millions of
different antibodies could fit in a limited number of genes. The answer is that antibody genes are pieced together from
widely scattered bits of DNA, and the possible combinations are nearly
endless. As this gene forms, it assembles segments that will determine
the variable-V, diversity-D, joining-J, and constant-C segments of this
antibody molecule, a typical IgM heavy chain.

13. T Cells
T cells contribute to
the immune defenses in two major ways. Some help regulate the complex
workings of the immune system, while others are cytotoxic and directly
contact infected cells and destroy them. Chief among the regulatory T cells are "helper/inducer" T
cells. They are needed to activate many immune cells, including B cells
and other T cells. Another subset of regulatory T cells acts to turn
off or suppress immune cells. Cytotoxic T cells help rid the body of cells that have been
infected by viruses as well as cells that have been transformed by
cancer. They are also responsible for the rejection of tissue and organ
grafts.

14. Cytokines
Cytokines are diverse and potent chemical messengers secreted by the cells of the immune system—and the chief tool of T cells.
Lymphocytes, including both T cells and B cells, secrete lymphokines, while monocytes and macrophages secrete monokines.
Binding
to specific receptors on target cells, cytokines recruit many other
cells and substances to the field of action. Cytokines encourage cell
growth, promote cell activation, direct cellular traffic, and destroy
target cells—including cancer cells. Because they serve as a messenger
between white cells, or leukocytes, many cytokines are also known as
interleukins.
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15. Natural Killer Cells
At least two types of lymphocytes are killer cells cytotoxic T cells and natural killer cells.
To
attack, cytotoxic T cells need to recognize a specific antigen, whereas
natural killer or NK cells do not. Both types contain granules filled
with potent chemicals, and both types kill on contact. The killer binds
to its target, aims its weapons, and delivers a burst of lethal
chemicals.

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 7:27 pm

16. Phagocytes and Granulocytes
Phagocytes are large white cells that can engulf and digest foreign invaders.
They
include monocytes, which circulate in the blood, and macrophages, which
are found in tissues throughout the body, as well as neutrophils, cells
that circulate in the blood but move into tissues where they are
needed. Macrophages are versatile cells; they act as scavengers, they
secrete a wide variety of powerful chemicals, and they play an
essential role in activating T cells. Neutrophils are not only phagocytes but also granulocytes:
they contain granules filled with potent chemicals. These chemicals, in
addition to destroying microorganisms, play a key role in acute
inflammatory reactions. Other types of granulocytes are eosinophils and
basophils. Mast cells are granule-containing cells in tissue.

17. Phagocytes in the Body
Specialized phagocytes are found in organs throughout the body.

18. Complement
The complement system consists of a series of proteins that work to "complement" the work of antibodies in destroying bacteria.
Complement
proteins circulate in the blood in an inactive form. The so-called
"complement cascade" is set off when the first complement molecule, C1,
encounters antibody bound to antigen in an antigen-antibody complex.
Each of the complement proteins performs its specialized job in turn,
acting on the molecule next in line. The end product is a cylinder that
punctures the cell membrane and, by allowing fluids and molecules to
flow in and out, dooms the target cell.

19. Mounting an Immune Response
Microbes
attempting to get into the body must first get past the skin and mucous
membranes, which not only pose a physical barrier but are rich in
scavenger cells and IgA antibodies. Next, they must elude a series of nonspecific defenses cells
and substances that attack all invaders regardless of the epitopes they
carry. These include patrolling scavenger cells, complement, and
various other enzymes and chemicals. Infectious agents that get past the nonspecific barriers
must confront specific weapons tailored just for them. These include
both antibodies and cells. Almost all antigens trigger both nonspecific
and specific responses.

20. Antigen Receptors
Both B cells and T cells carry customized receptor molecules that allow them to recognize and respond to their specific targets.
The
B cell's antigen-specific receptor is a sample of the antibody it is
prepared to manufacture; it recognizes antigen in its natural state. The T cell receptor system is more complex. A T cell can
recognize an antigen only after the antigen is processed and presented
to it by a so-called antigen-presenting cell, in combination with a
special type of cell marker. The T4 T cell's receptor looks for an antigen that has been
broken down by an immune system cell such as a macrophage or a B cell
and combined with a marker, known as a class II protein, carried by
immune cells. The T8 T cell's receptor recognizes an antigen fragment
produced within the cell, combined with a class I protein; class I
proteins are found on virtually all body cells. This complicated arrangement assures that T cells act only on precise targets and at close range.

21. Activation of B Cells to Make Antibody
The B cell uses its receptor to bind a matching antigen, which it proceeds to engulf and process.
Then
it combines a fragment of antigen with its special marker, the class II
protein. This combination of antigen and marker is recognized and bound
by a T cell carrying a matching receptor. The binding activates the T
cell, which then releases lymphokines—interleukins—that transform the B
cell into an antibody- secreting plasma cell.

22. Activation of T Cells: Helper and Cytotoxic
After
an antigen-presenting cell such as a macrophage has ingested and
processed an antigen, it presents the antigen fragment, along with a
class II marker protein, to a matching helper T cell with a T4
receptor. The binding prompts the macrophage to release interleukins that allow the T cell to mature.
A
cytotoxic T cell recognizes antigens such as virus proteins,which are
produced within a cell, in combination with a class I self-marker
protein. With the cooperation of a helper T cell, the cytotoxic T cell
matures. Then, when the mature cytotoxic T cell encounters its specific
target antigen combined with a class I marker protein—for instance, on
a body cell that has been infected with a virus—it is ready to attack
and kill the target cell.

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 7:30 pm

موضوع: رد: immunity pictures الأربعاء 16 يناير 2008, 7:34 pm

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