By endocytosis or phagocytosis, exogenous antigens are taken into the antigen-presenting cells ( APCs ) and processed into fragments.

APCs are fundamentally different from the previously used armoured half-tracks in that they offer a higher level of protection from artillery burst fragments, and greater mobility in more terrain types.

Modern IFVs are well-armed infantry carriers, differencing from earlier APCs by their heavier armament allowing them to give direct-fire support during an assault.

They are often used as APCs because of their carrying ability and heavy protection.

It is believed that the seized vehicles ( which included 15 Belgian Army Pandur APCs leased to Beninise army troops ) and parts have been used to equip the Military of Equatorial Guinea, and such seizure are considered by some as an act of piracy.

IFVs are similar to armoured personnel carriers ( APCs ), designed to transport a section or squad of infantry ( generally between five and ten men ) and their equipment.

They are differentiated from APCs — which are purely transport vehicles, armed only for self defence — because they are designed to give direct fire support to the dismounted infantry and so usually have significantly enhanced armament.

Mechanized infantry are infantry equipped with armored personnel carriers ( APCs ) or infantry fighting vehicles ( IFVs ) for transport and combat ( see also mechanized force ).

Most APCs and IFVs are fully tracked, or are all-wheel drive vehicles ( 6 × 6 or 8 × 8 ), for mobility across rough ground.

A recent trend seen in the Israel Defense Forces, the Armed Forces of the Russian Federation is the development and introduction of exceptionally well-armored APCs ( HAPC ) such as the IDF Achzarit which are converted from obsolete Main Battle Tanks ( such as the Russian T-55 ).

Many APCs and IFVs currently under development are intended for rapid deployment by aircraft.

RPGs are very effective against armored vehicles such as armored personnel carriers ( APCs ).

Nevertheless they are often surprisingly effective ; ceramic upgrades to Canadian M-113s were carried out in the 1990s, after it was realized that it would offer more protection than newly built APCs like the M2 Bradley.

Helper T cells become activated when they are presented with peptide antigens by MHC class II molecules, which are expressed on the surface of antigen presenting cells ( APCs ).

The principal functions of B-cells are to make antibodies against antigens, to perform the role of antigen-presenting cells ( APCs ), and to develop into memory B cells after activation by antigen interaction.

Class II MHC proteins are generally only found on the surface of specialised antigen-presenting cells ( APCs ).

Some APCs also bind native ( or unprocessed ) antigens to their surface, such as follicular dendritic cells, but unprocessed antigens do not interact with T cells and are not involved in their activation.

At the present time, infantry in the Finnish Army are designated either as infantry or Jäger troops, specifically mechanized infantry or motorised infantry using APCs or vehicles such as Sisu Nasu.

Including prototypes and export versions there are over a hundred variants including self-propelled gun, anti-aircraft systems, APCs, and ATGM versions.

** XA-203, the last generation APC replacing the oldest vehicles of the XA-185 series, except for regular APCs and ambulances, there are also the following versions:

Dendritic cells ( DCs ), which are the primary antigen-presenting cells ( APCs ), of the donor tissue migrate to the recipient's peripheral lymphoid tissue ( lymphoid follicles and lymph nodes ), and present the donor's self peptides to the recipient's lymphocytes ( immune cells residing in lymphoid tissues ).

APCs then present the fragments to T helper cells ( CD4 < sup >+</ sup >) by the use of class II histocompatibility molecules on their surface.

T cells cannot bind native antigens, but require that they be processed by APCs, whereas B cells can be activated by native ones.

The earliest armored personnel carriers ( APCs ) produced by Brazil, in the 1960s, benefited directly from some of the technology developed by Brazil's dynamic automotive industry.

* Gila APCs ( 6, intended for police use ; paid for by the Canadian government )

As of 2012, major equipment items reported by the IISS included ten T-55 tanks ( marked as potentially unserviceable ), 5 AMX-13 light tanks, 34 reconnaissance vehicles, 10 BMP-1 / 2 armoured infantry fighting vehicles, 41 wheeled APCs, and 36 + artillery pieces.

Some nations distinguish between mechanized and armored infantry, designating troops carried by APCs as mechanized and those in IFVs as armored.

During the South African Border War, the Soviet RPGs used by SWAPO guerilllas and their Angolan supporters posed a serious threat to South Africa's lightly armored APCs, which could be easily targeted as soon as they stopped to disembark troops.

RPGs were used with great effect in the famous Battle of Vukovar by the Croatian army, during which more than 300 tanks, APCs and vehicles were put out of action.

In the course of the Battle of Grodno ( September 20 – September 22 ), the Red Army lost some hundred men ( by the Polish sources ; by the Soviet sources-57 killed and 159 wounded ) and also 19 tanks and 4 APCs destroyed or damaged.

This allowed the PLA to seize seven US-made M48A5 main battle tanks ( MBTs ) and a number of Staghound armoured cars, AMX-13 light tanks and M113 APCs for its own armoured corps, further strengthened in 1985 with the arrival of some 70 T-54 / 55 MBTs, BTR-152, BTR-60 and BMP-1 APCs supplied on loan by Syria and the USSR, which they employed in the War of the Camps waged that same year against Nasserite and PLO militias in west Beirut.

MHC class II can be conditionally expressed by all cell types, but normally occurs only on professional antigen-presenting cells ( APCs ): macrophages, B cells, and especially dendritic cells ( DCs ).

As of now BMD-1 and vehicles based on it are used by the following units of Russian Army or are stationed in following bases ( this list does not include BTR-D APCs and BTR-D variants ):

Achzarit APCs took part in Operation Rainbow in Rafah, after a comparatively lightly armored M113 APC was destroyed by an RPG.

Some 2500 Casspir series APCs were built by TFM of South Africa, which was subsequently taken over by Reumech OMC.

The α-and β-subunits contains extracellular binding sites for peptides that are presented by the major histocompatibility complex ( MHC ) class I and class II proteins on the surface of antigen presenting cells ( APCs ).

They were intended as a stop-gap vehicle for use until the first Panhard M3 VTT APCs entered service in 1972.

More sophisticated systems for tanks and APCs exist that use various techniques ( including scanning lasers and coupled radio systems ) to allow more precise targeting of armored vehicles.

They were intended as a stop-gap vehicle for use until the first Panhard M3 VTT APCs entered service in 1972.

Platforms used include both trucks and heavier combat vehicles such as APCs and tanks, which add protection from aircraft, artillery, and small arms fire for front line deployment.

Platforms used include both trucks and heavier combat vehicles such as APCs and tanks, which add protection from aircraft, artillery, and small arms fire for front line deployment.

Apart from a mere ten M2 Half Track Cars, the Guardia suffered from a chronic shortage of light armoured personnel carriers ( APCs ) for its infantry units, forcing them to rely on their extensive fleet of transport and liaison vehicles.

However, with there being relatively few gaps in the Nui Dat perimeter wide enough for the APCs, Roberts had been forced to take a circuitous route through the base to the south-east.

After completing the dangerous crossing without incident, Roberts left one carrier and its infantry to secure it and to act as a guide for Townsend, while the remaining seven APCs continued to move towards the battle.

Townsend requested the remaining APCs bring out 6 RAR headquarters, C Company and a section of mortars the following morning, while D Company, 5 RAR would also be placed under his command for the operation.

The key reasons for D Company's success included their superior radio communications which had allowed Stanley to co-ordinate the fires of the guns at Nui Dat, the firepower of the artillery itself which had repeatedly broken up the assaulting Viet Cong formations, the resupply of D Company by helicopter which had prevented them from running out of ammunition, and the firepower and mobility of the APCs in the relief force which finally broke the Viet Cong's will to fight.

Despite experiences of the Second Sino-Japanese War, APCs were viewed as too slow compared to wheeled trucks and there was not much effort for their development in the army.

The M20 was primarily used as a command vehicle and for forward reconnaissance, but many vehicles also served as APCs and cargo carriers.

In this model CTLA 4 reverses the classic TCR-induced ‘ stop signal ’ needed for firm contact between T cells and antigen-presenting cells ( APCs ).