MHC (major histocompatibility complex) molecules are a group of proteins found on the surface of cells that play a crucial role in the immune system. They are responsible for presenting antigens, or foreign substances, to T cells, which are a type of white blood cell. This process helps the immune system distinguish between self and non-self cells, and plays a key role in the body's ability to recognize and respond to pathogens such as viruses and bacteria. MHC molecules are highly diverse, allowing the immune system to recognize a wide range of antigens. **

Viruses can affect MHC II by downregulating its expression on the surface of infected cells, which can impair the ability of the immune system to recognize and respond to the virus. Some viruses have evolved mechanisms to interfere with the antigen presentation process, leading to reduced MHC II expression and antigen presentation. This can ultimately result in evasion of the immune response and allow the virus to persist and replicate within the host. Additionally, viruses can also manipulate the MHC II antigen presentation pathway to promote their own survival and replication. **

MHC (major histocompatibility complex) molecules belong to the specific immune system. They play a crucial role in presenting antigens to T cells, which triggers a specific immune response against pathogens. MHC molecules are highly diverse and specific to each individual, allowing the immune system to distinguish between self and non-self antigens. This specificity is essential for mounting an effective immune response against pathogens while avoiding attacking the body's own cells. **

The caricature of the summit conference in Helsinki shows the leaders of the United States and Russia, Donald Trump and Vladimir Putin, sitting at a table with Trump holding a puppet string attached to Putin. This caricature is a satirical representation of the perception that Trump is under the control or influence of Putin, suggesting that Putin is pulling the strings and manipulating Trump. The image reflects the controversy and speculation surrounding the relationship between the two leaders and the potential influence of Russia on the United States. **

A symposium is a formal gathering or meeting where experts in a particular field come together to discuss and exchange ideas on a specific topic. It is often organized as a series of presentations, panel discussions, and Q&A sessions, allowing participants to share their knowledge and insights with each other. Symposia are commonly held in academic and professional settings, providing a platform for networking, collaboration, and learning within a specific discipline or industry. **

"Der Kongress tanzt" is a German phrase that translates to "The Congress Dances" in English. The phrase originated from the Congress of Vienna in 1814-1815, where European diplomats and leaders gathered to reorganize Europe after the Napoleonic Wars. The phrase is a metaphor for the diplomatic and political maneuvering that took place during the Congress, likening it to a dance where participants carefully navigated their relationships and alliances. It reflects the complex and intricate nature of international diplomacy and negotiations during this historic event. **

A convention is a formal agreement or a set of accepted norms and practices that govern behavior in a particular context or industry. It is a customary way of doing things that is widely recognized and followed by a group of people. Conventions help to establish consistency, order, and predictability in social interactions or professional settings. They can vary across different cultures, societies, or fields of study. **

The G20 summit is a meeting of the leaders of the world's 20 largest economies, representing both developed and developing countries. The summit provides a platform for these leaders to discuss and coordinate on global economic issues, such as trade, finance, and development. It is an opportunity for countries to work together to address common challenges and promote global economic stability and growth. The G20 summit also serves as a forum for leaders to address pressing international issues, such as climate change, terrorism, and global health crises. **