Comparison of Lymphoid Organs and Lymphoid Cells

 Lymphoid Organs and Lymphoid Cells Comparison

Immune System | Biotechnology

The focus of today’s discussion would be the Comparison between lymphoid cells and the lymphoid organs.

The two major keywords of this topic are lymphoid cells and lymphoid organs are well explained before in the previous discussions and will guide us in better understanding of the current topic.

Please follow my posts, Cells of Immune System and Organsof Immune System, if not gone through before, this post will help you in understanding the terms and facts and includes both ‘Cells of Immune system’ as well as ‘Organs of Immune System’ in Biotechnology, which will be coming further in this topic.

So, let’s start discussion on Lymphoid Cells and Lymphoid Organs, later in this post we will try to correctly compare both of them.

Immune Cells or Lymphoid Cells and Immune organs or Lymphoid Organs :

The main cells or lymphocytes which are involved in an immune response are known as immune cells or lymphoid cells.

The organs which are involved in the production of immune cells and their respective reactions are called immune organs or lymphoid organs.

Mainly lymphoid cells and lymphoid organs are present only in vertebrates.

Only vertebrates possess adaptive immunity*, which is governed by antibodies and T cells.

All vertebrates have gut associated lymphoid tissue (GALT) and most of them have a simple type of spleen and thymus.

Most Importantly, bone marrow and lymph nodes are not present in all the vertebrates.

At cellular level, both lymphoid cells and lymphoid organs also exhibit some differences.

Lymphocytes having antigen specific receptors on their surface are required to mount an adaptive immune response.

Jawed vertebrates are the only example to have B and T lymphocytes and support adaptive immune response.

Evolutionary Line Of Development of Lymphoid Organs and Lymphoid Cells:

The process of evolutionary development of  lymphoid organs and lymphoid cells evolved in the following way.

·        In Invertebrates:

Hematopoietic stem cell give rise to phagocytes, which shows germ line encoded pattern recognition receptors.

·        In Jawless Vertebrates :

The hematopoietic system also produces lymphocyte like cells which express somatically diversified antigen (Ag) receptors.

·        In hypothetical intermediate I :

The hematopoietic stem cells also start producing a second lineage of lymphocyte like cells, which shows structural invariant proto TCR (T cell receptor).

·        In hypothetical intermediate II :

Occurrence of transformation of structurally variant proto TCR into somatically diversible VDJ type TCR through transposon mediated insertion.

·        In Jawed Vertebrates :

The hematopoietic stem cell finally gives rise to B lymphocytes or cells which express somatically diversified antigen receptors.

Step by Step tabular Data on Comparative evolution of Lymphoid Organs and Lymphoid Cells:

Steps	Lymphoid Cells	Lymphoid Organs
I	Myeloid cells including phagocytes	Myeloid tissue
II	Myeloid cells with B lymphocyte like cells	Lympho- myeloid tissue (spleen)
III	Addition of proto T cells	Lympho- myeloid tissue (spleen and thymus )
IV	T cell expressing modern TCR (T cell receptor)	Lympho- myeloid tissue ( bone marrow or equivalent and thymus)
V	T cell expressing modern TCR (T cell receptor) and B cells express modern BCR (B cell receptor)	Lympho- myeloid tissue ( bone marrow and thymus)

The above information gives you a better understanding on the evolution of lymphoid organs and lymphoid cells and a better and easy comparison between the lymphoid organs and lymphoid cells.

I believe after reading this post, you can explain about ‘Evolution of Lymphoid Organs and Lymphoid Cells’ and ‘Comparison between Lymphoid Organs and Lymphoid Cells’ by yourself now.

There is lot more to share, Keep in touch and stay happy.

Happy Lymphoid Organs and Lymphoid Cells Learning!!!

Disorders of Immune System or Immune System Dysfunctions

Immune System Disorders and It’s ConsequencesImmune System | Biotechnology

In this post we are going to discuss about the various disorders or dysfunctions of the Immune System and their impact on our life. This is a follow up post after Functions of Immune system.

So far we have discussed Immune System Basic Concepts, Innate Immunity, Cells of Immune System, AdaptiveImmune System, Organs of Immune System and Functions of Immune system.

Consider all previous (Mentioned above) lessons including this one as an overview of what I am going to explain in my upcoming lessons. If you have not gone through previous lessons then this is the right time to build your basics on these topics and get required information which is actually essential for every student and help you to follow my explanations in next posts.

Since I am always suggesting learning with patience and step by step learning is the best way to get the correct and useful information.

Now let’s begin with the topic,

Improper functioning of the Immune System can lead to the over activity or abnormal low activity of our immune response.

In Immune studies, the immune response to an antigen works as a “two edged sword”. It either protects or harms the host.

The Disorders of Immune System can be categorized under the following type:

·        Allergy or Asthma

·        Graft rejection and Graft versus host disease

·        Autoimmune disease

·        Immunodeficiency

·        Allergy or Asthma :

In simple words, Allergy is a process which triggers an allergic reaction.

When immune system goes the wrong way, the allergic reaction is produced by normal human body processes.

It can be like on touching a house pet or reaction to plant pollens.

Asthma is the severe symptom of immune over reaction or an allergy.

Asthma is a chronic disease of lungs, due to inflammation in the airway which results in reversible airway obstruction.

Symptoms of Asthma are:

Ø Wheezing

Ø Tightness and heaviness in chest

Ø Breathlessness

·        Graft rejection and Graft versus host disease :

Skin and organ transplants from one person to the other are known as grafts.

These grafts are rejected by the host body in most of the cases due to   dysfunctioning of the immune system. They are also known as tissue rejection.

To minimize graft rejection, drugs are used to suppress the immune system of host, which makes the host more prone to various kinds of infection.

Graft versus host disease (GVHD) occurs when host cells are recognized as foreign by the donor cells and start attacking them.

Symptoms can be mild, severe or fatal also.

Graft versus host disease   is of two types:

Ø Acute GVHD

Ø Chronic GVHD

i.                   Acute GVHD :

It comprises of the following feature:

a.     Cause severe acute morbidity (weight   loss, lack of activity) leading to death.

b.     Tissue necrosis in the target organs.

c.      Th1 cytokines are produced.

d.     Immune deficiency is there.

e.      Anti host cytotoxic T lymphocytes (CTL) are reactive.

ii.                 Chronic GVHD :

The important characteristic points are:

a.     More survival rate with chronic morbidity.

b.     Occurrence of fibrosis and inflammatory changes.

c.      Production of Th2 cytokines.

d.     Auto antibodies are produced

e.      There is no anti host cytotoxic T lymphocytes reactivity.

·        Autoimmune Disease :

The function of immune system is to recognize and reject foreign body.

Due to improper functioning of immune system, the body itself starts getting damaged by its own immune system.

This process is known as Auto immune disease.

i.                   Symptoms :

The symptoms vary according to the person’s immune system and the disease caused.

They include:

Ø Anxiety or depression

Ø Blood sugar change

Ø Digestive problems

Ø Fatigue and dizziness

Ø High body temperature

Ø Extreme sensitivity to cold in hands and feet

ii.                 Common Autoimmune diseases :

They are:

Ø Hashimoto’s thyroiditis

Ø Rheumatoid arthritis

Ø Type I diabetes

Ø Lupus erythematosus

Ø Crohn’s disease

Ø Grave’s disease

iii.              Factors associated with Auto immune disease :

Among various reasons responsible for having autoimmune disease, some factors are also kept in mind, which are related for happening of autoimmune disease.

They are:

Ø Environmental Factors

Ø Hormonal Influence

Ø Genetic Physiology

·        Immunodeficiency :

Sometimes, immune system has its own problems within itself, which are called disorders.

Immunodeficiency is a disease which is caused when immune system is less active than its normal working phenomenon.

It can be caused as a result of genetic diseases or by a viral infection, such as AIDS (Acquired Immunodeficiency Syndrome) which is caused by retrovirus HIV (Human Immunodeficiency Virus).

i.                   Types of Immunodeficiency :

   They are categorized under following three heads:

Ø Primary Immunodeficiency

Ø Severe Combined Immunodeficiency (SCIDS)

Ø Secondary Immunodeficiency

Ø Primary Immunodeficiency :

It is genetic based and involves lack of   B cell or T cell activity.

During B cell defect, there is a lack of Antibodies (Ab).

In T cell disorder, either thymus is missing or working abnormally.

Ø Severe Combined Immunodeficiency (SCIDS) :

In SCIDS, both parts of the lymphocyte system are missing or not working properly.

There is no adaptive immune response.

Ø Secondary Immunodeficiency :

This type of immunodeficiency is acquired i.e. caused due to damage after birth.

The reasons might be viral infection, drugs or radiations.

ii.                 Symptoms :

The common symptoms associated with immunodeficiency are:

Ø Pneumonia, sinus and chronic cough

Ø Cough up blood

Ø Difficulty in breathing

Ø Diarrhea

Ø Enlarged spleen

Here, we have discussed all the key points related to ImmuneSystem Disorders or Immune System Dysfunctions.

In further coming discussions, we will pick and discuss each topic extensively.

Till then, keep learning and clearing your concepts and enjoy.

There is lot more to share, Keep in touch and stay happy.

Happy BioTechnology Learning!!!