Immunological memory is built through cellular conversations, especially via the immune synapse. (´remembering infections´) 

𝗜𝗺𝗺𝘂𝗻𝗼𝗹𝗼𝗴𝗶𝗰𝗮𝗹 𝗠𝗲𝗺𝗼𝗿𝘆 
𝘈𝘥𝘢𝘱𝘵𝘪𝘷𝘦 𝘮𝘦𝘮𝘰𝘳𝘺: After infection or vaccination, some B and T cells survive as long-lived memory cells. Upon re-exposure, they respond faster and stronger than naïve cells [1]. 
𝘐𝘯𝘯𝘢𝘵𝘦  𝘵𝘳𝘢𝘪𝘯𝘦𝘥 𝘪𝘮𝘮𝘶𝘯𝘪𝘵𝘺: Already in Day 3 we discussed Prof. Mihai Netea’s work, showing that innate cells (monocytes, NK cells) can adapt epigenetically, ´remembering´ past encounters, even without antigen-specific receptors [2]. (https://www.linkedin.com/posts/activity-7372871729943048192-Y5qh?utm_source=share&utm_medium=member_desktop&rcm=ACoAAC7R33oBU_8RoYPHRDoVcF5C0OEYKzEXkxY) 

Immunological memory is 𝘯𝘰𝘵 𝘦𝘹𝘤𝘭𝘶𝘴𝘪𝘷𝘦 𝘵𝘰 𝘢𝘥𝘢𝘱𝘵𝘪𝘷𝘦 𝘪𝘮𝘮𝘶𝘯𝘪𝘵𝘺. From plasma cells producing antibodies for decades to NK cells altered by viral exposure, the immune system keeps different kinds of ´notebooks´. 

𝗧𝗵𝗲 𝗜𝗺𝗺𝘂𝗻𝗲 𝗦𝘆𝗻𝗮𝗽𝘀𝗲 
The immune synapse is the organized interface where a T cell meets an antigen-presenting cell (APC). 
It includes TCR–MHC-peptide interactions, adhesion molecules, and signaling clusters (SMACs: supramolecular activation clusters) [3]. 
Function: it stabilizes contact, ensures signal quality/duration, and coordinates downstream activation, proliferation, and differentiation. 

𝗔𝗻𝗮𝗹𝗼𝗴𝘆: Imagine a Zoom webinar with screen-sharing. The APC shares the ´slide´ (antigen peptide on MHC), the T cell listens and responds, and co-stimulatory molecules act like moderators ´unmuting the microphone´. Without the full setup, the message gets lost or ignored. 

𝗚𝗲𝗿𝗺𝗮𝗻 𝗖𝗼𝗻𝘁𝗿𝗶𝗯𝘂𝘁𝗶𝗼𝗻𝘀 
Christian Kurts (Bonn), whom we already discussed in Day 6, studies how antigen presentation quality decides whether a T cell becomes tolerant, effector, or long-lived memory [4]. 
Andreas Radbruch (Berlin, DRFZ) defined how long-lived plasma cells, residing in bone marrow niches, sustain humoral immunological memory for decades – the molecular basis for lifelong vaccine protection [5]. 

𝗧𝗮𝗸𝗲𝗮𝘄𝗮𝘆 
Immunological memory ensures the immune system learns from the past. The immune synapse is the classroom where that lesson is taught. Together, they bridge past experiences with future protection — in both adaptive and trained innate immunity. 

Stay tuned for 𝗗𝗮𝘆 𝟴: 𝗕𝗮𝗿𝗿𝗶𝗲𝗿𝘀 𝗼𝗳 𝗶𝗺𝗺𝘂𝗻𝗶𝘁𝘆 

𝗥𝗲𝗳𝗲𝗿𝗲𝗻𝗰𝗲𝘀 
1. DOI: 10.1126/science.272.5258.54 
2. DOI: 10.1126/science.aaf1098 
3. DOI: 10.1158/2326-6066.CIR-14-0161 
4. DOI: 10.1038/nri2780 
5. DOI: 10.1038/nri1886  

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