WEBVTT NOTE This file was generated by Descript 00:00:01.620 --> 00:00:05.640 Most vaccines work by training the immune system to recognize 00:00:05.640 --> 00:00:07.950 harmful viruses or bacteria. 00:00:08.370 --> 00:00:12.840 Vaccines are usually given before we actually get infected as a form 00:00:12.840 --> 00:00:17.730 of preventative medicine, but cancer researchers are also developing 00:00:17.730 --> 00:00:22.890 vaccines that could be used as treatments after cancer has been found. 00:00:23.360 --> 00:00:27.050 The idea is to teach the body's immune system to recognize the 00:00:27.050 --> 00:00:29.000 cancer cells and then kill them. 00:00:29.690 --> 00:00:31.165 There are several ways to do this. 00:00:32.159 --> 00:00:35.220 Every cell in the body is surrounded by a cell membrane 00:00:35.220 --> 00:00:37.140 with proteins embedded in it. 00:00:37.500 --> 00:00:39.930 Inside cells, there are proteins too. 00:00:40.530 --> 00:00:44.160 Cancer cells make proteins found nowhere else in the body. 00:00:44.580 --> 00:00:46.500 Think of them like a barcode. 00:00:46.890 --> 00:00:51.239 The simplest type of cancer vaccine takes a single protein commonly found 00:00:51.239 --> 00:00:55.800 in one type of cancer and teaches the immune system to react to it. 00:00:56.370 --> 00:00:57.209 The protein. 00:00:57.270 --> 00:01:01.350 Or antigen is injected into the body where an immune cell called 00:01:01.350 --> 00:01:03.690 a dendritic cell, ingests it. 00:01:04.290 --> 00:01:08.460 The dendritic cell then activates another class of immune cells called 00:01:08.520 --> 00:01:11.700 T cells, and these attack the cancer. 00:01:12.630 --> 00:01:16.350 This method is straightforward and hospitals could have a supply 00:01:16.350 --> 00:01:20.190 of vaccines in the fridge for the most common types of cancer. 00:01:20.730 --> 00:01:24.390 But in trials, these vaccines haven't always worked. 00:01:24.630 --> 00:01:29.730 So researchers are now trying to target patient's tumors more specifically. 00:01:30.509 --> 00:01:36.060 As tumors grow, they mutate, which means they change the unique proteins that. 00:01:36.130 --> 00:01:42.070 Each patient's tumor acquires, as it mutates, are known as neoantigens, and 00:01:42.070 --> 00:01:47.710 these neoantigens are being tested as the basis for personalized vaccines. 00:01:48.250 --> 00:01:50.919 First, a sample of the patient's tumor is taken. 00:01:51.399 --> 00:01:55.660 The tumor cells contain messenger, RNA, which carries the genetic 00:01:55.660 --> 00:01:57.910 instructions for making proteins. 00:01:58.300 --> 00:02:02.199 The mRNA is extracted and sequenced along with the cells. 00:02:02.245 --> 00:02:07.285 DNA to identify the instructions for the tumor's, unique proteins. 00:02:07.375 --> 00:02:08.650 Its neoantigens. 00:02:09.614 --> 00:02:13.845 The ones predicted to most powerfully stimulate the immune system are 00:02:13.845 --> 00:02:17.954 selected and injected into the body for the dendritic cells. 00:02:17.954 --> 00:02:24.105 To find this kind of bespoke mRNA vaccine is showing exciting promise. 00:02:24.105 --> 00:02:29.620 For treating melanoma and pancreatic cancers, there's another way to 00:02:29.620 --> 00:02:33.880 make personalized vaccines that doesn't involve genetic sequencing. 00:02:34.510 --> 00:02:38.740 Again, a tumor sample is taken, but this time the proteins are 00:02:38.740 --> 00:02:40.480 extracted from the cancer cells. 00:02:40.765 --> 00:02:45.865 And then without identifying the proteins introduced to a sample of the patient's 00:02:45.865 --> 00:02:48.415 dendritic cells in a Petri dish. 00:02:48.925 --> 00:02:53.245 When the dendritic cells are injected back into the body, they stimulate T 00:02:53.245 --> 00:02:55.975 cells to recognize and attack the cancer. 00:02:56.940 --> 00:03:01.649 Personalized vaccines may be very powerful, but making them a new for every 00:03:01.649 --> 00:03:04.530 patient is costly and time consuming. 00:03:05.100 --> 00:03:09.420 So scientists are also working on off the shelf treatments where 00:03:09.420 --> 00:03:13.739 the vaccination process occurs completely within the patient's body. 00:03:14.520 --> 00:03:19.260 Patients are given drugs that activate dendritic cells as well as a treatment 00:03:19.260 --> 00:03:22.440 like radiotherapy that kills cancer cells. 00:03:23.070 --> 00:03:27.360 The dying cancer cells release their proteins, which are mopped up by 00:03:27.360 --> 00:03:29.520 the switched on dendritic cells. 00:03:30.090 --> 00:03:34.890 These cells then present the cancer proteins to T cells, stimulating 00:03:34.890 --> 00:03:37.170 the T cells to attack the cancer. 00:03:38.355 --> 00:03:41.685 All of these approaches are still being developed and tested 00:03:42.075 --> 00:03:44.025 if trials continue to go well. 00:03:44.265 --> 00:03:49.575 Vaccines that boost the body's own immune defenses look set to become another 00:03:49.575 --> 00:03:52.335 tool in our efforts to defeat cancer.