Microbiology and Immunology

WORLD OF MICROBIOLOGY AND IMMUNOLOGY Montagnier, Luc

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Word of the importance of Monod’s work began to

spread, and in 1958 he was invited to become professor of

biochemistryat the Sorbonne, a position he accepted condi-

tional to his retaining his post at the Pasteur Institute. At the

Sorbonne, Monod was the chair of chemistry of metabolism,

but in April 1966, his position was renamed the chair of

molecular biologyin recognition of his research in creating the

new science. Monod, Jacob, Lwoff won the 1965 Nobel Prize

for physiology or medicine for their discovery of how genes

regulate cell metabolism.

See alsoBacterial growth and division; Microbial genetics;

Molecular biology and molecular genetics

MMononucleosis, infectiousONONUCLEOSIS, INFECTIOUS

Infectious mononucleosis is an illness caused by the Epstein-

Barr virus. The symptoms of “mono,” as the disease is collo-

quially called, include extreme fatigue, fever, sore throat,

enlargement of the lymph nodes in the neck, armpit, and

throat, sore muscles, loss of appetite, and an enlarged spleen.

More infrequently, an individual will experience nausea, hep-

atitis, jaundice (which indicates malfunction of the liver),

severe headache, chest pain, and difficulty breathing. Children

may display only a few or none of these symptoms, while all

can be present in adolescents.

The illness can be passed from person to person via the

saliva. In adolescents, mononucleosis was once known as “the

kissing disease” since kissing is a route of transmission of the

Epstein-Barr virus. Given the relative ease of transmissions,

epidemic outbreaks of mononucleosis can occur in environ-

ments such as schools, hospitals and the workplace.

Infectious mononucleosis is usually self-limiting.

Recovery occurs with time and rest, and is usually complete

with no after effects. Analgesics can help relieve the symp-

toms of pain and fever in adults. However, children should

avoid taking aspirin, as use of the drug in viral illnesses is

associated with the development of Reye syndrome, which

can cause liver failure and even death.

Recovery from mononucleosis is not always complete.

In some people there can be a decrease in the number of red

and white blood cells, due either to damage to the bone mar-

row (where the blood cells are produced) or to enhanced

destruction of the red blood cells (a condition known as

hemolytic anemia). Another temporary complication of the ill-

ness is weakened or paralyzed facial muscles on one side of

the face. The condition, which is called Bell’s palsy, leaves the

individual with a drooping look to one side of the face. Much

more rarely, very severe medical complications can arise.

These include rupture of the spleen, swelling of the heart

(myocarditis), malfunction of the central nervous system, and

Guillain-Barré syndrome. The latter condition is a paralysis

resulting from disruption of nervous system function.

The illness is diagnosed in a number of ways. Clinically,

the presence of fever, and inflammationof the pharynx and the

lymph nodes are hallmarks of the illness. Secondly, the so-

called “mono spot” test will demonstrate an elevated amount

of antibodyto the virus in the bloodstream. A third diagnostic

feature of the illness is an increase in the number of white

blood cells. These cells, which are also called lymphocytes,

help fight viral infections.

Antibodies to the Epstein-Barr virus persist for a long

time. Therefore, one bout of the illness usually bestows long-

lasting immunityin an individual. Testing has demonstrated

that most people have antibodies to the Epstein-Barr virus.

Thus, most people have been infected with the virus at some

point in their lives, but have displayed only a few minor symp-

toms or no symptoms at all. Many children are infected with

the virus and either display no symptoms or become tran-

siently ill with one of the retinue of infections acquired during

the first few years of life. When the initial infection occurs

during adolescence, the development of mononucleosis results

35–50% of the time. Understanding of the reasons for this fail-

ure to infect could lead to a vaccineto prevent infectious

mononucleosis. As of 2002, there is no vaccine available.

The Epstein-Barr virus that is responsible for the illness

is a member of the herpesvirus family. The virus is found all

over the world and is one of the most common human viruses.

In infectious mononucleosis, the virus infects and makes new

copies of itself in the epithelial cells of the oropharynx. Also,

the virus invades the B cellsof the immune system.

For most patients, the infection abates after two to four

weeks. Several more weeks may pass before the spleen

resumes its normal size. A period of low activity is usually

prescribed after a bout of mononucleosis, to protect the spleen

and to help energy levels return to normal.

Epstein-Barr virus is usually still present after an infec-

tion has ended. The virus becomes dormant in some cells of

the throat, in the blood, and in some cells of the immune sys-

tem. Very rarely in some individuals, the latent virus may be

linked to the appearance years later of two types of cancers;

Burkitt’s lymphoma and nasopharyngeal carcinoma.

See alsoViruses and responses to viral infection

MMontagnier, Luc ONTAGNIER, LUC(1932- )

French virologist

Luc Montagnier, Distinguished Professor at Queens College

in New York and the Institut Pasteur in Paris, has devoted his

career to the study of viruses. He is perhaps best known for his

1983 discovery of the human immunodeficiency virus(HIV),

which has been identified as the cause of acquired immunode-

ficiencysyndrome (AIDS). However, in the twenty years

before the onset of the AIDS epidemic, Montagnier made

many significant discoveries concerning the nature of viruses.

He made major contributions to the understanding of how

viruses can alter the genetic information of host organisms,

and significantly advanced cancer research. His investigation

of interferon, one of the body’s defenses against viruses, also

opened avenues for medical cures for viral diseases.

Montagnier’s ongoing research focuses on the search for an

AIDS vaccineor cure.

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