CD-4

CD-4 or CD4 may refer to:

CD4

In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells. It was discovered in the late 1970s and was originally known as leu-3 and T4 (after the OKT4 monoclonal antibody that reacted with it) before being named CD4 in 1984. In humans, the CD4 protein is encoded by the CD4 gene.

CD4+ T helper cells are white blood cells that are an essential part of the human immune system. They are often referred to as CD4 cells, T-helper cells or T4 cells. They are called helper cells because one of their main roles is to send signals to other types of immune cells, including CD8 killer cells, which then destroy the infectious particle. If CD4 cells become depleted, for example in untreated HIV infection, or following immune suppression prior to a transplant, the body is left vulnerable to a wide range of infections that it would otherwise have been able to fight.

Structure

Like many cell surface receptors/markers, CD4 is a member of the immunoglobulin superfamily.

United States

Coordinates: 40°N 100°W / 40°N 100°W / 40; -100

The United States of America (USA), commonly referred to as the United States (U.S.) or America, is a federal republic composed of 50 states, a federal district, five major territories and various possessions. The 48 contiguous states and Washington, D.C., are in central North America between Canada and Mexico. The state of Alaska is in the northwestern part of North America and the state of Hawaii is an archipelago in the mid-Pacific. The territories are scattered about the Pacific Ocean and the Caribbean Sea. At 3.8 million square miles (9.842 million km²) and with over 320 million people, the country is the world's third or fourth-largest by total area and the third most populous. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration from many countries. The geography and climate of the United States are also extremely diverse, and the country is home to a wide variety of wildlife.

U-S-A!

"U-S-A!" is a chant of the United States of America's initials popular in expressing American pride and supporting American national sports teams. The chant was documented at the 1972 Summer Olympics in Munich, Germany, during the basketball tournament final between the United States and the Soviet Union, but was popularized after being yelled by fans during the 1980 Winter Olympics, held in Lake Placid, New York, where the U.S. men's ice hockey team defeated the Soviet Union in what became known as the "Miracle on Ice", later moving on to beat Finland for the gold medal. The origin of the cheer is unknown, although there are reports which pre-date the 1972 Olympics. It was chanted during the finals of the 1500 meter event and the long jump at the 1936 Summer Olympics and can be heard in Leni Riefenstahl's Festival of Nations documentary.

The chant can be used in other community events, such as at political rallies.

Origins

Use in sports

During the U.S.'s 7–3 win over Czechoslovakia in the 1980 Winter Olympic tournament's second game, Sandy MacDonald and David Claiborne began chanting "U-S-A! U-S-A!" in support of the American hockey team as the Americans scored a decisive win over one of the best teams in the world. The chant became a fixture of the team's remaining games and gained national attention during the famous "Miracle on Ice" game against the Soviet Union. Since that time, American sports fans have spontaneously chanted "U-S-A! U-S-A!" at many international events, and during times of patriotic fervor. Interestingly, it was Sandy MacDonald's idea to start the chant and Mr. MacDonald was born and raised in Canada.

U.S.A. (United State of Atlanta)

U.S.A. (United State of Atlanta) (stylised on the cover as U.nited S.tate of A.tlanta) is the fourth studio album by Atlanta-based rap duo Ying Yang Twins. The album debuted at No. 2 on the Billboard 200 with approximately 201,000 copies sold in the first week released making the duo's highest charting album to date. The album was eventually certified platinum by the RIAA with an excess of 1 million copies sold. It was also released in a chopped and screwed version.

The Collipark remix "(I Got That) Boom Boom" with Britney Spears was initially going to appear on the album but didn't make the final cut.

Track listing

References