findAssociatedClones {NAIR}

Identify TCR/BCR Clones in a Neighborhood Around Each Associated Sequence

Description

Part of the workflow Searching for Associated TCR/BCR Clusters. Intended for use following findAssociatedSeqs() and prior to buildAssociatedClusterNetwork().

Given multiple samples of bulk Adaptive Immune Receptor Repertoire Sequencing (AIRR-Seq) data and a vector of associated sequences, identifies for each associated sequence a global "neighborhood" comprised of clones with TCR/BCR sequences similar to the associated sequence.

Usage

findAssociatedClones(

  ## Input ##
  file_list, input_type,
  data_symbols = NULL,
  header, sep, read.args,
  sample_ids =
    paste0("Sample", 1:length(file_list)),
  subject_ids = NULL,
  group_ids,
  seq_col,
  assoc_seqs,

  ## Neighborhood Criteria ##
  nbd_radius = 1,
  dist_type = "hamming",
  min_seq_length = 6,
  drop_matches = NULL,

  ## Output ##
  subset_cols = NULL,
  output_dir,
  output_type = "rds",
  verbose = FALSE

)

Arguments

file_list

A character vector of file paths, or a list containing connections and file paths. Each element corresponds to a single file containing the data for a single sample. Passed to loadDataFromFileList().

input_type

A character string specifying the file format of the sample data files. Options are "table", "txt", "tsv", "csv", "rds" and "rda". Passed to loadDataFromFileList().

data_symbols

Used when input_type = "rda". Specifies the name of each sample's data frame within its respective Rdata file. Passed to loadDataFromFileList().

header

For values of input_type other than "rds" and "rda", this argument can be used to specify a non-default value of the header argument to read.table(), read.csv(), etc.

sep

For values of input_type other than "rds" and "rda", this argument can be used to specify a non-default value of the sep argument to read.table(), read.csv(), etc.

read.args

For values of input_type other than "rds" and "rda", this argument can be used to specify non-default values of optional arguments to read.table(), read.csv(), etc. Accepts a named list of argument values. Values of header and sep in this list take precedence over values specified via the header and sep arguments.

sample_ids

A character or numeric vector of sample IDs, whose length matches that of file_list. Each entry is assigned as the sample ID to the corresponding entry of file_list.

subject_ids

An optional character or numeric vector of subject IDs, whose length matches that of file_list. Used to assign a subject ID to each sample.

group_ids

A character or numeric vector of group IDs whose length matches that of file_list. Used to assign each sample to a group. The two groups represent the levels of the binary variable of interest.

seq_col

Specifies the column of each sample's data frame containing the TCR/BCR sequences. Accepts a character string containing the column name or a numeric scalar containing the column index.

assoc_seqs

A character vector containing the TCR/BCR sequences associated with the binary variable of interest.

nbd_radius

The maximum distance (based on dist_type) between an associated sequence and other TCR/BCR sequences belonging to its neighborhood. Lower values require sequences to be more similar to an associated sequence in order to belong to its neighborhood.

dist_type

Specifies the function used to quantify the similarity between sequences. The similarity between two sequences determines their pairwise distance, with greater similarity corresponding to shorter distance. Valid options are "hamming" (the default), which uses hamDistBounded(), and "levenshtein", which uses levDistBounded().

min_seq_length

Clones with TCR/BCR sequences below this length will be removed. Passed to filterInputData() when loading each sample.

drop_matches

Passed to filterInputData(). Accepts a character string containing a regular expression (see regex). Checks TCR/BCR sequences for a pattern match using grep(). Those returning a match are dropped. By default, sequences containing any of the characters *, | or _ are dropped.

subset_cols

Controls which columns of the AIRR-Seq data from each sample are included in the output. Accepts a character vector of column names or a numeric vector of column indices. The default NULL includes all columns. Passed to filterInputData().

output_dir

A file path to a directory for saving the output. A valid output directory is required, since no output is returned in R. The specified directory will be created if it does not already exist.

output_type

A character string specifying the file format to use for saving the output. Valid options are "rda", "csv", "csv2", "tsv" and"table". For "rda", data frames are named data in the R environment. For the remaining options, write.table() is called with row.names = TRUE.

verbose

Logical. If TRUE, generates messages about the tasks performed and their progress, as well as relevant properties of intermediate outputs. Messages are sent to stderr().

Details

For each associated sequence, its neighborhood is defined to include all clones with TCR/BCR sequences that are sufficiently similar to the associated sequence. The arguments dist_type and nbd_radius control how the similarity is measured and the degree of similarity required for neighborhood membership.

For each associated sequence, a data frame is saved to an individual file. The data frame contains one row for each clone in the associated sequence's neighborhood (from all samples). It includes variables for sample ID, group ID and (if provided) subject ID, as well as variables from the AIRR-Seq data.

The files saved by this function are intended for use with buildAssociatedClusterNetwork(). See the Searching for Associated TCR/BCR Clusters article on the package website for more details.

Value

Returns TRUE, invisibly. The function is called for its side effects.

Author(s)

Brian Neal ([e-mail])

References

Hai Yang, Jason Cham, Brian Neal, Zenghua Fan, Tao He and Li Zhang. (2023). NAIR: Network Analysis of Immune Repertoire. Frontiers in Immunology, vol. 14. doi: 10.3389/fimmu.2023.1181825

Webpage for the NAIR package

Searching for Associated TCR/BCR Clusters article on package website

See Also

findAssociatedSeqs() buildAssociatedClusterNetwork()

Examples

set.seed(42)

## Simulate 30 samples from two groups (treatment/control) ##
n_control <- n_treatment <- 15
n_samples <- n_control + n_treatment
sample_size <- 30 # (seqs per sample)
base_seqs <- # first five are associated with treatment
  c("CASSGAYEQYF", "CSVDLGKGNNEQFF", "CASSIEGQLSTDTQYF",
    "CASSEEGQLSTDTQYF", "CASSPEGQLSTDTQYF",
    "RASSLAGNTEAFF", "CASSHRGTDTQYF", "CASDAGVFQPQHF")
# Relative generation probabilities by control/treatment group
pgen_c <- matrix(rep(c(rep(1, 5), rep(30, 3)), times = n_control),
                 nrow = n_control, byrow = TRUE)
pgen_t <- matrix(rep(c(1, 1, rep(1/3, 3), rep(2, 3)), times = n_treatment),
                 nrow = n_treatment, byrow = TRUE)
pgen <- rbind(pgen_c, pgen_t)
simulateToyData(
  samples = n_samples,
  sample_size = sample_size,
  prefix_length = 1,
  prefix_chars = c("", ""),
  prefix_probs = cbind(rep(1, n_samples), rep(0, n_samples)),
  affixes = base_seqs,
  affix_probs = pgen,
  num_edits = 0,
  output_dir = tempdir(),
  no_return = TRUE
)

## Step 1: Find Associated Sequences ##
sample_files <-
  file.path(tempdir(),
            paste0("Sample", 1:n_samples, ".rds")
  )
group_labels <- c(rep("reference", n_control),
                  rep("comparison", n_treatment))
associated_seqs <-
  findAssociatedSeqs(
    file_list = sample_files,
    input_type = "rds",
    group_ids = group_labels,
    seq_col = "CloneSeq",
    min_seq_length = NULL,
    drop_matches = NULL,
    min_sample_membership = 0,
    pval_cutoff = 0.1
  )
head(associated_seqs[, 1:5])

## Step 2: Find Associated Clones ##
dir_step2 <- tempfile()
findAssociatedClones(
  file_list = sample_files,
  input_type = "rds",
  group_ids = group_labels,
  seq_col = "CloneSeq",
  assoc_seqs = associated_seqs$ReceptorSeq,
  min_seq_length = NULL,
  drop_matches = NULL,
  output_dir = dir_step2
)

## Step 3: Global Network of Associated Clusters ##
associated_clusters <-
  buildAssociatedClusterNetwork(
    file_list = list.files(dir_step2,
                           full.names = TRUE
    ),
    seq_col = "CloneSeq",
    size_nodes_by = 1.5,
    print_plots = TRUE
  )